Diff: rfc8941v1.xml - rfc8941.xml

	rfc8941v1.xml	rfc8941.xml

	<?xml version="1.0" encoding="UTF-8"?>	<?xml version='1.0' encoding='utf-8'?>

	<!-- Note: updated by Chris 07/14/20 and formatted by AP-->

	<!DOCTYPE rfc SYSTEM "rfc2629-xhtml.ent">	<!DOCTYPE rfc SYSTEM "rfc2629-xhtml.ent">

		<rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902" docName="draft
	<rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902"	-ietf-httpbis-header-structure-19" number="8941" submissionType="IETF" category=
	docName="draft-ietf-httpbis-header-structure-19" number="8941"	"std" consensus="true" obsoletes="" updates="" xml:lang="en" tocInclude="true" s
	submissionType="IETF" category="std" consensus="true" obsoletes=""	ortRefs="true" symRefs="true" tocDepth="3" version="3">
	updates="" xml:lang="en" tocInclude="true" sortRefs="true" symRefs="true"
	tocDepth="3" version="3">

	<!-- xml2rfc v2v3 conversion 2.46.0 -->	<!-- xml2rfc v2v3 conversion 2.46.0 -->
	<front>	<front>
	<title>Structured Field Values for HTTP</title>	<title>Structured Field Values for HTTP</title>
	<seriesInfo name="RFC" value="8941"/>	<seriesInfo name="RFC" value="8941"/>
	<author initials="M." surname="Nottingham" fullname="Mark Nottingham">	<author initials="M." surname="Nottingham" fullname="Mark Nottingham">
	<organization>Fastly</organization>	<organization>Fastly</organization>
	<address>	<address>

		<postal>
		<city>Prahran</city>
		<region>VIC</region>
		<country>Australia</country>
		</postal>
	<email>mnot@mnot.net</email>	<email>mnot@mnot.net</email>
	<uri>https://www.mnot.net/</uri>	<uri>https://www.mnot.net/</uri>
	</address>	</address>
	</author>	</author>
	<author initials="P-H." surname="Kamp" fullname="Poul-Henning Kamp">	<author initials="P-H." surname="Kamp" fullname="Poul-Henning Kamp">
	<organization>The Varnish Cache Project</organization>	<organization>The Varnish Cache Project</organization>
	<address>	<address>
	<email>phk@varnish-cache.org</email>	<email>phk@varnish-cache.org</email>
	</address>	</address>
	</author>	</author>

	<date month="October" year="2020" />	<date month="November" year="2020"/>
	<area>Applications and Real-Time</area>	<area>Applications and Real-Time</area>
	<workgroup>HTTP</workgroup>	<workgroup>HTTP</workgroup>


	<!-- [rfced] Please insert any keywords (beyond those that appear in
	the title) for use on https://www.rfc-editor.org/search. -->

	<abstract>	<abstract>
	<t>This document describes a set of data types and associated algorithms	<t>This document describes a set of data types and associated algorithms
	that are intended to make it easier and safer to define and handle HTTP	that are intended to make it easier and safer to define and handle HTTP
	header and trailer fields, known as "Structured Fields", "Structured	header and trailer fields, known as "Structured Fields", "Structured
	Headers", or "Structured Trailers". It is intended for use by	Headers", or "Structured Trailers". It is intended for use by
	specifications of new HTTP fields that wish to use a common syntax that	specifications of new HTTP fields that wish to use a common syntax that
	is more restrictive than traditional HTTP field values.</t>	is more restrictive than traditional HTTP field values.</t>
	</abstract>	</abstract>


	</front>	</front>
	<middle>	<middle>

	<section anchor="introduction" numbered="true" toc="default">	<section anchor="introduction">
	<name>Introduction</name>	<name>Introduction</name>
	<t>Specifying the syntax of new HTTP header (and trailer) fields is an	<t>Specifying the syntax of new HTTP header (and trailer) fields is an

	onerous task; even with the guidance in <xref target="RFC7231" sectionForm at="of" section="8.3.1"/>, there are many decisions -- and	onerous task; even with the guidance in <xref target="RFC7231" section="8. 3.1"/>, there are many decisions -- and
	pitfalls -- for a prospective HTTP field author.</t>	pitfalls -- for a prospective HTTP field author.</t>
	<t>Once a field is defined, bespoke parsers and serializers often need	<t>Once a field is defined, bespoke parsers and serializers often need
	to be written, because each field value has a slightly different handling	to be written, because each field value has a slightly different handling
	of what looks like common syntax.</t>	of what looks like common syntax.</t>
	<t>This document introduces a set of common data structures for use in	<t>This document introduces a set of common data structures for use in
	definitions of new HTTP field values to address these problems. In	definitions of new HTTP field values to address these problems. In
	particular, it defines a generic, abstract model for them, along with a	particular, it defines a generic, abstract model for them, along with a

	concrete serialization for expressing that model in HTTP <xref	concrete serialization for expressing that model in HTTP <xref target="RFC
	target="RFC7230" format="default"/> header and trailer fields.</t>	7230"/> header and trailer fields.</t>
	<t>An HTTP field that is defined as a "Structured Header" or "Structured	<t>An HTTP field that is defined as a "Structured Header" or "Structured
	Trailer" (if the field can be either, it is a "Structured Field") uses	Trailer" (if the field can be either, it is a "Structured Field") uses
	the types defined in this specification to define its syntax and basic	the types defined in this specification to define its syntax and basic
	handling rules, thereby simplifying both its definition by specification	handling rules, thereby simplifying both its definition by specification
	writers and handling by implementations.</t>	writers and handling by implementations.</t>
	<t>Additionally, future versions of HTTP can define alternative	<t>Additionally, future versions of HTTP can define alternative
	serializations of the abstract model of these structures, allowing	serializations of the abstract model of these structures, allowing
	fields that use that model to be transmitted more efficiently without	fields that use that model to be transmitted more efficiently without
	being redefined.</t>	being redefined.</t>
	<t>Note that it is not a goal of this document to redefine the syntax of	<t>Note that it is not a goal of this document to redefine the syntax of
	existing HTTP fields; the mechanisms described herein are only intended	existing HTTP fields; the mechanisms described herein are only intended
	to be used with fields that explicitly opt into them.</t>	to be used with fields that explicitly opt into them.</t>

	<t><xref target="specify" format="default"/> describes how to specify a	<t><xref target="specify"/> describes how to specify a
	Structured Field.</t>	Structured Field.</t>

	<t><xref target="types" format="default"/> defines a number of abstract	<t><xref target="types"/> defines a number of abstract
	data types that can be used in Structured Fields.</t>	data types that can be used in Structured Fields.</t>
	<t>Those abstract types can be serialized into and parsed from HTTP	<t>Those abstract types can be serialized into and parsed from HTTP

	field values using the algorithms described in <xref target="text"	field values using the algorithms described in <xref target="text"/>.</t>
	format="default"/>.</t>	<section anchor="strict">
	<section anchor="strict" numbered="true" toc="default">
	<name>Intentionally Strict Processing</name>	<name>Intentionally Strict Processing</name>


	<t>This specification intentionally defines strict parsing and	<t>This specification intentionally defines strict parsing and
	serialization behaviors using step-by-step algorithms; the only error	serialization behaviors using step-by-step algorithms; the only error
	handling defined is to fail the operation altogether.</t>	handling defined is to fail the operation altogether.</t>
	<t>It is designed to encourage faithful implementation and therefore	<t>It is designed to encourage faithful implementation and therefore
	good interoperability. Therefore, an implementation that tried to be	good interoperability. Therefore, an implementation that tried to be
	helpful by being more tolerant of input would make interoperability	helpful by being more tolerant of input would make interoperability
	worse, since that would create pressure on other implementations to	worse, since that would create pressure on other implementations to
	implement similar (but likely subtly different) workarounds.</t>	implement similar (but likely subtly different) workarounds.</t>
	<t>In other words, strict processing is an intentional feature of this	<t>In other words, strict processing is an intentional feature of this
	specification; it allows non-conformant input to be discovered and	specification; it allows non-conformant input to be discovered and

	skipping to change at line 100 ¶	skipping to change at line 89 ¶
	implement similar (but likely subtly different) workarounds.</t>	implement similar (but likely subtly different) workarounds.</t>
	<t>In other words, strict processing is an intentional feature of this	<t>In other words, strict processing is an intentional feature of this
	specification; it allows non-conformant input to be discovered and	specification; it allows non-conformant input to be discovered and
	corrected by the producer early and avoids both interoperability and	corrected by the producer early and avoids both interoperability and
	security issues that might otherwise result.</t>	security issues that might otherwise result.</t>
	<t>Note that as a result of this strictness, if a field is appended to	<t>Note that as a result of this strictness, if a field is appended to
	by multiple parties (e.g., intermediaries or different components in	by multiple parties (e.g., intermediaries or different components in
	the sender), an error in one party's value is likely to cause the	the sender), an error in one party's value is likely to cause the
	entire field value to fail parsing.</t>	entire field value to fail parsing.</t>
	</section>	</section>

	<section anchor="notational-conventions" numbered="true" toc="default">	<section anchor="notational-conventions">
	<name>Notational Conventions</name>	<name>Notational Conventions</name>
	<t>	<t>
	The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",	The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
	"<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL	"<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL
	NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>",	NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>",
	"<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",	"<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
	"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are	"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are
	to be interpreted as	to be interpreted as

	described in BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/>	described in BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/>
	when, and only when, they appear in all capitals, as shown here.	when, and only when, they appear in all capitals, as shown here.
	</t>	</t>
	<t>This document uses algorithms to specify parsing and serialization	<t>This document uses algorithms to specify parsing and serialization

	behaviors and the Augmented Backus-Naur Form (ABNF) notation of <xref	behaviors and the Augmented Backus-Naur Form (ABNF) notation of <xref tar
	target="RFC5234" format="default"/> to illustrate expected syntax in	get="RFC5234"/> to illustrate expected syntax in
	HTTP header fields. In doing so, it uses the VCHAR, SP, DIGIT, ALPHA,	HTTP header fields. In doing so, it uses the VCHAR, SP, DIGIT, ALPHA,

	and DQUOTE rules from <xref target="RFC5234" format="default"/>. It	and DQUOTE rules from <xref target="RFC5234"/>. It
	also includes the tchar and OWS rules from <xref target="RFC7230"	also includes the tchar and OWS rules from <xref target="RFC7230"/>.</t>
	format="default"/>.</t>
	<t>When parsing from HTTP fields, implementations <bcp14>MUST</bcp14> ha ve behavior	<t>When parsing from HTTP fields, implementations <bcp14>MUST</bcp14> ha ve behavior
	that is indistinguishable from following the algorithms. If there is	that is indistinguishable from following the algorithms. If there is
	disagreement between the parsing algorithms and ABNF, the specified	disagreement between the parsing algorithms and ABNF, the specified
	algorithms take precedence.</t>	algorithms take precedence.</t>
	<t>For serialization to HTTP fields, the ABNF illustrates their	<t>For serialization to HTTP fields, the ABNF illustrates their
	expected wire representations, and the algorithms define the	expected wire representations, and the algorithms define the
	recommended way to produce them. Implementations <bcp14>MAY</bcp14> vary from the	recommended way to produce them. Implementations <bcp14>MAY</bcp14> vary from the
	specified behavior so long as the output is still correctly handled by	specified behavior so long as the output is still correctly handled by

	the parsing algorithm.</t>	the parsing algorithm described in <xref target="text-parse"/>.</t>
	</section>	</section>
	</section>	</section>

	<section anchor="specify" numbered="true" toc="default">	<section anchor="specify">
	<name>Defining New Structured Fields</name>	<name>Defining New Structured Fields</name>
	<t>To specify an HTTP field as a Structured Field, its authors need to:</t >	<t>To specify an HTTP field as a Structured Field, its authors need to:</t >

	<ul spacing="normal">	<ul>
	<li>Normatively reference this specification. Recipients and	<li>Normatively reference this specification. Recipients and
	generators of the field need to know that the requirements of this	generators of the field need to know that the requirements of this
	document are in effect.</li>	document are in effect.</li>
	<li>Identify whether the field is a Structured Header (i.e., it can	<li>Identify whether the field is a Structured Header (i.e., it can
	only be used in the header section -- the common case), a Structured	only be used in the header section -- the common case), a Structured
	Trailer (only in the trailer section), or a Structured Field	Trailer (only in the trailer section), or a Structured Field
	(both).</li>	(both).</li>

	<li>Specify the type of the field value; either List (<xref	<li>Specify the type of the field value; either List (<xref target="list
	target="list" format="default"/>), Dictionary (<xref	"/>), Dictionary (<xref target="dictionary"/>), or Item (<xref target="item"/>).
	target="dictionary" format="default"/>), or Item (<xref target="item"	</li>
	format="default"/>).</li>
	<li>Define the semantics of the field value.</li>	<li>Define the semantics of the field value.</li>
	<li>Specify any additional constraints upon the field value, as well	<li>Specify any additional constraints upon the field value, as well
	as the consequences when those constraints are violated.</li>	as the consequences when those constraints are violated.</li>
	</ul>	</ul>
	<t>Typically, this means that a field definition will specify the	<t>Typically, this means that a field definition will specify the
	top-level type -- List, Dictionary, or Item -- and then define its	top-level type -- List, Dictionary, or Item -- and then define its
	allowable types and constraints upon them. For example, a header	allowable types and constraints upon them. For example, a header
	defined as a List might have all Integer members, or a mix of types; a	defined as a List might have all Integer members, or a mix of types; a
	header defined as an Item might allow only Strings, and additionally	header defined as an Item might allow only Strings, and additionally
	only strings beginning with the letter "Q", or strings in	only strings beginning with the letter "Q", or strings in

	lowercase. Likewise, Inner Lists (<xref target="inner-list"	lowercase. Likewise, Inner Lists (<xref target="inner-list"/>) are only va
	format="default"/>) are only valid when a field definition explicitly	lid when a field definition explicitly
	allows them.</t>	allows them.</t>

	<t>When parsing fails, the entire field is ignored (see <xref	<t>When parsing fails, the entire field is ignored (see <xref target="text
	target="text-parse" format="default"/>); in most situations, violating	-parse"/>); in most situations, violating
	field-specific constraints should have the same effect. Thus, if a	field-specific constraints should have the same effect. Thus, if a
	header is defined as an Item and required to be an Integer, but a String	header is defined as an Item and required to be an Integer, but a String
	is received, the field will by default be ignored. If the field requires	is received, the field will by default be ignored. If the field requires
	different error handling, this should be explicitly specified.</t>	different error handling, this should be explicitly specified.</t>
	<t>Both Items and Inner Lists allow parameters as an extensibility	<t>Both Items and Inner Lists allow parameters as an extensibility
	mechanism; this means that values can later be extended to accommodate	mechanism; this means that values can later be extended to accommodate
	more information, if need be. To preserve forward compatibility, field	more information, if need be. To preserve forward compatibility, field
	specifications are discouraged from defining the presence of an	specifications are discouraged from defining the presence of an

	unrecognized Parameter as an error condition.</t>	unrecognized parameter as an error condition.</t>
	<t>To further assure that this extensibility is available in the future,	<t>To further assure that this extensibility is available in the future,
	and to encourage consumers to use a complete parser implementation, a	and to encourage consumers to use a complete parser implementation, a

	field definition can specify that "grease" Parameters be added by	field definition can specify that "grease" parameters be added by
	senders. A specification could stipulate that all Parameters that fit a	senders. A specification could stipulate that all parameters that fit a
	defined pattern are reserved for this use and then encourage them to be	defined pattern are reserved for this use and then encourage them to be
	sent on some portion of requests. This helps to discourage recipients	sent on some portion of requests. This helps to discourage recipients
	from writing a parser that does not account for Parameters.</t>	from writing a parser that does not account for Parameters.</t>
	<t>Specifications that use Dictionaries can also allow for forward	<t>Specifications that use Dictionaries can also allow for forward
	compatibility by requiring that the presence of -- as well as value and	compatibility by requiring that the presence of -- as well as value and

	type associated with -- unknown members be ignored. Later, specifications	type associated with -- unknown members be ignored. Subsequent specificati ons
	can then add additional members, specifying constraints on them as	can then add additional members, specifying constraints on them as
	appropriate.</t>	appropriate.</t>

	<t>An extension to a structured field can then require that an entire	<t>An extension to a Structured Field can then require that an entire
	field value be ignored by a recipient that understands the extension if	field value be ignored by a recipient that understands the extension if
	constraints on the value it defines are not met.</t>	constraints on the value it defines are not met.</t>
	<t>A field definition cannot relax the requirements of this	<t>A field definition cannot relax the requirements of this
	specification because doing so would preclude handling by generic	specification because doing so would preclude handling by generic
	software; they can only add additional constraints (for example, on the	software; they can only add additional constraints (for example, on the
	numeric range of Integers and Decimals, the format of Strings and	numeric range of Integers and Decimals, the format of Strings and
	Tokens, the types allowed in a Dictionary's values, or the number of	Tokens, the types allowed in a Dictionary's values, or the number of
	Items in a List). Likewise, field definitions can only use this	Items in a List). Likewise, field definitions can only use this
	specification for the entire field value, not a portion thereof.</t>	specification for the entire field value, not a portion thereof.</t>
	<t>This specification defines minimums for the length or number of	<t>This specification defines minimums for the length or number of
	various structures supported by implementations. It does not specify	various structures supported by implementations. It does not specify
	maximum sizes in most cases, but authors should be aware that HTTP	maximum sizes in most cases, but authors should be aware that HTTP
	implementations do impose various limits on the size of individual	implementations do impose various limits on the size of individual
	fields, the total number of fields, and/or the size of the entire header	fields, the total number of fields, and/or the size of the entire header
	or trailer section.</t>	or trailer section.</t>
	<t>Specifications can refer to a field name as a "structured header	<t>Specifications can refer to a field name as a "structured header
	name", "structured trailer name", or "structured field name" as	name", "structured trailer name", or "structured field name" as
	appropriate. Likewise, they can refer its field value as a "structured	appropriate. Likewise, they can refer its field value as a "structured
	header value", "structured trailer value", or "structured field value" as	header value", "structured trailer value", or "structured field value" as
	necessary.	necessary.

	<!-- [rfced] May we update this sentence to clarify "their"?

	Original:
	Field definitions are encouraged to use
	the ABNF rules beginning with "sf-" defined in this specification;
	other rules in this specification are not intended for their use.

	Perhaps (a little redundant, but perhaps more clear):
	Field definitions are encouraged to use
	the ABNF rules beginning with "sf-" defined in this specification;
	other ABNF rules in this specification are not intended to be used in field
	definitions.
	Field definitions are encouraged to use the ABNF rules	Field definitions are encouraged to use the ABNF rules
	beginning with "sf-" defined in this specification; other rules in this	beginning with "sf-" defined in this specification; other rules in this

	specification are not intended for their use.</t>	specification are not intended to be used in field definitions.</t>
	<t>For example, a fictitious Foo-Example header field might be specified	<t>For example, a fictitious Foo-Example header field might be specified
	as:</t>	as:</t>


	<!-- [rfced] Throughout, we have marked the example as <sourcecode>. There is	<blockquote>
	no "example" type; do you want to mark the <sourcecode> with no type as	<t>42. Foo-Example Header</t>
	pseudocode? The current list of types is available here:
	https://www.rfc-editor.org/materials/sourcecode-types.txt



	<sourcecode><![CDATA[
	42. Foo-Example Header
	]]></sourcecode>
	<t>The Foo-Example HTTP header field conveys information about how	<t>The Foo-Example HTTP header field conveys information about how
	much Foo the message has.</t>	much Foo the message has.</t>


	<t>Foo-Example is an Item Structured Header [RFCxxxx]. Its value <bcp14>MUST</bc	<t>Foo-Example is an Item Structured Header [RFCxxxx]. Its value MUST be
	p14> be	an Integer (Section 3.3.1 of [RFC8941]). Its ABNF is:</t>
	an Integer (Section Y.Y of [RFCxxxx]). Its ABNF is:</t>


	<sourcecode type="abnf"><![CDATA[	<artwork>
	Foo-Example = sf-integer	Foo-Example = sf-integer
	]]></sourcecode>	</artwork>


	<t>Its value indicates the amount of Foo in the message, and it <bcp14>MUST</bcp	<t>Its value indicates the amount of Foo in the message, and it MUST
	14>	be between 0 and 10, inclusive; other values MUST cause
	be between 0 and 10, inclusive; other values <bcp14>MUST</bcp14> cause
	the entire header field to be ignored.</t>	the entire header field to be ignored.</t>


	<!--[rfced] Since only 1 parameter ("foourl") is being defined below,	<t>The following parameter is defined:</t>
	may we update the text as follows ('parameter' instead of 'parameters'?)

	Original:
	The following parameters are defined:
	* A Parameter whose name is "foourl", and whose value is a String
	(Section Y.Y of [RFCxxxx]), conveying the Foo URL
	for the message. See below for processing requirements.


	Perhaps:	<ul>
	The following parameter is defined:	<li>A parameter whose name is "foourl", and whose value is a String
	* A Parameter whose name is "foourl", and whose value is a String	(Section 3.3.3 of [RFC8941]), conveying the Foo URL
	(Section Y.Y of [RFCxxxx]), conveying the Foo URL	for the message. See below for processing requirements.</li>
	for the message. See below for processing requirements.	</ul>
	<t>The following parameters are defined:
	* A Parameter whose name is "foourl", and whose value is a String
	(Section Y.Y of [RFCxxxx]), conveying the Foo URL
	for the message. See below for processing requirements.</t>


	<t>"foourl" contains a URI-reference (<xref target="RFC3986"	<t>"foourl" contains a URI-reference (Section 4.1 of [RFC3986]). If
	sectionFormat="of" section="4.1"/>). If
	its value is not a valid URI-reference, the entire header field	its value is not a valid URI-reference, the entire header field

	<bcp14>MUST</bcp14> be ignored. If its value is a relative reference (<xref	MUST be ignored. If its value is a relative reference (Section 4.2
	target="RFC3986" sectionFormat="of" section="4.2"/>), it <bcp14>MUST</bcp14>	of [RFC3986]), it MUST be resolved (Section 5 of [RFC3986]) before
	be resolved (<xref target="RFC3986" sectionFormat="of" section="5"/>) before
	being used.</t>	being used.</t>

	<t>For example:</t>	<t>For example:</t>


	<sourcecode type="" name=""><![CDATA[	<artwork>
	Foo-Example: 2; foourl="https://foo.example.com/"	Foo-Example: 2; foourl="https://foo.example.com/"
	]]></sourcecode>	</artwork>
		</blockquote>

	</section>	</section>

	<section anchor="types" numbered="true" toc="default">	<section anchor="types">
	<name>Structured Data Types</name>	<name>Structured Data Types</name>
	<t>This section defines the abstract types for Structured Fields. The	<t>This section defines the abstract types for Structured Fields. The
	ABNF provided represents the on-wire format in HTTP field values.</t>	ABNF provided represents the on-wire format in HTTP field values.</t>
	<t>In summary:</t>	<t>In summary:</t>

	<ul spacing="normal">	<ul>
	<li>There are three top-level types that an HTTP field can be defined	<li>There are three top-level types that an HTTP field can be defined
	as: Lists, Dictionaries, and Items.</li>	as: Lists, Dictionaries, and Items.</li>
	<li>Lists and Dictionaries are containers; their members can be Items	<li>Lists and Dictionaries are containers; their members can be Items
	or Inner Lists (which are themselves arrays of Items).</li>	or Inner Lists (which are themselves arrays of Items).</li>

	<li>Both Items and Inner Lists can be parameterized with key/value pairs .</li>	<li>Both Items and Inner Lists can be Parameterized with key/value pairs .</li>
	</ul>	</ul>

	<section anchor="list" numbered="true" toc="default">	<section anchor="list">
	<name>Lists</name>	<name>Lists</name>
	<t>Lists are arrays of zero or more members, each of which can be an	<t>Lists are arrays of zero or more members, each of which can be an

	Item (<xref target="item" format="default"/>) or an Inner List (<xref	Item (<xref target="item"/>) or an Inner List (<xref target="inner-list"/
	target="inner-list" format="default"/>), both of which can be	>), both of which can be
	Parameterized (<xref target="param" format="default"/>).</t>	Parameterized (<xref target="param"/>).</t>
	<t>The ABNF for Lists in HTTP fields is:</t>	<t>The ABNF for Lists in HTTP fields is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-list = list-member *( OWS "," OWS list-member )	sf-list = list-member *( OWS "," OWS list-member )
	list-member = sf-item / inner-list	list-member = sf-item / inner-list

	]]></sourcecode>	</sourcecode>
	<t>Each member is separated by a comma and optional whitespace. For	<t>Each member is separated by a comma and optional whitespace. For
	example, a field whose value is defined as a List of Strings could	example, a field whose value is defined as a List of Strings could
	look like:</t>	look like:</t>

	<sourcecode><![CDATA[	<sourcecode type="http-message">
	Example-StrList: "foo", "bar", "It was the best of times."	Example-List: "foo", "bar", "It was the best of times."
	]]></sourcecode>	</sourcecode>
	<t>An empty List is denoted by not serializing the field at all. This	<t>An empty List is denoted by not serializing the field at all. This
	implies that fields defined as Lists have a default empty value.</t>	implies that fields defined as Lists have a default empty value.</t>
	<t>Note that Lists can have their members split across multiple lines	<t>Note that Lists can have their members split across multiple lines

	inside a header or trailer section, as per <xref target="RFC7230"	inside a header or trailer section, as per <xref target="RFC7230" section
	sectionFormat="of" section="3.2.2"/>; for example, the following are	="3.2.2"/>; for example, the following are
	equivalent:</t>	equivalent:</t>

	<sourcecode><![CDATA[	<sourcecode type="http-message">
	Example-Hdr: foo, bar	Example-List: foo, bar
	]]></sourcecode>	</sourcecode>
	<t>and</t>	<t>and</t>

	<sourcecode><![CDATA[	<sourcecode type="http-message">
	Example-Hdr: foo	Example-List: foo
	Example-Hdr: bar	Example-List: bar
	]]></sourcecode>	</sourcecode>

	<t>However, individual members of a List cannot be safely split	<t>However, individual members of a List cannot be safely split

	between lines; see <xref target="text-parse" format="default"/>	between lines; see <xref target="text-parse"/>
	for details.</t>	for details.</t>
	<t>Parsers <bcp14>MUST</bcp14> support Lists containing at least 1024 me mbers. Field	<t>Parsers <bcp14>MUST</bcp14> support Lists containing at least 1024 me mbers. Field
	specifications can constrain the types and cardinality of individual	specifications can constrain the types and cardinality of individual
	List values as they require.</t>	List values as they require.</t>

	<section anchor="inner-list" numbered="true" toc="default">	<section anchor="inner-list">
	<name>Inner Lists</name>	<name>Inner Lists</name>

	<t>An Inner List is an array of zero or more Items (<xref	<t>An Inner List is an array of zero or more Items (<xref target="item
	target="item" format="default"/>). Both the individual Items and the	"/>). Both the individual Items and the
	Inner List itself can be Parameterized (<xref target="param"	Inner List itself can be Parameterized (<xref target="param"/>).</t>
	format="default"/>).</t>
	<t>The ABNF for Inner Lists is:</t>	<t>The ABNF for Inner Lists is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	inner-list = "(" SP [ sf-item ( 1SP sf-item ) SP ] ")"	inner-list = "(" SP [ sf-item ( 1SP sf-item ) SP ] ")"
	parameters	parameters

	]]></sourcecode>	</sourcecode>
	<t>Inner Lists are denoted by surrounding parenthesis, and	<t>Inner Lists are denoted by surrounding parenthesis, and
	their values are delimited by one or more spaces. A field whose value i s	their values are delimited by one or more spaces. A field whose value i s
	defined as a List of Inner Lists of Strings could look like:</t>	defined as a List of Inner Lists of Strings could look like:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-StrListList: ("foo" "bar"), ("baz"), ("bat" "one"), ()	Example-List: ("foo" "bar"), ("baz"), ("bat" "one"), ()
	]]></sourcecode>	</sourcecode>
	<t>Note that the last member in this example is an empty Inner List.</ t>	<t>Note that the last member in this example is an empty Inner List.</ t>
	<t>A header field whose value is defined as a List of Inner Lists	<t>A header field whose value is defined as a List of Inner Lists
	with Parameters at both levels could look like:</t>	with Parameters at both levels could look like:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-ListListParam: ("foo"; a=1;b=2);lvl=5, ("bar" "baz");lvl=1	Example-List: ("foo"; a=1;b=2);lvl=5, ("bar" "baz");lvl=1
	]]></sourcecode>	</sourcecode>
	<t>Parsers <bcp14>MUST</bcp14> support Inner Lists containing at least 256	<t>Parsers <bcp14>MUST</bcp14> support Inner Lists containing at least 256
	members. Field specifications can constrain the types and	members. Field specifications can constrain the types and
	cardinality of individual Inner List members as they require.</t>	cardinality of individual Inner List members as they require.</t>
	</section>	</section>

	<section anchor="param" numbered="true" toc="default">	<section anchor="param">
	<name>Parameters</name>	<name>Parameters</name>
	<t>Parameters are an ordered map of key-value pairs that are	<t>Parameters are an ordered map of key-value pairs that are

	associated with an Item (<xref target="item" format="default"/>) or	associated with an Item (<xref target="item"/>) or
	Inner List (<xref target="inner-list" format="default"/>).	Inner List (<xref target="inner-list"/>).

	<!--[rfced] Should the section reference for "parameterized" be
	Section 3.1.2 instead of Section 3.3?

	Original:
	The keys are unique within the scope the Parameters they occur within,
	and the values are bare items (i.e., they themselves cannot be
	parameterized; see Section 3.3).

	Perhaps:
	The keys are unique within the scope the Parameters they occur within,
	and the values are bare items (i.e., they themselves cannot be
	parameterized; see Section 3.1.2).
	The keys	The keys
	are unique within the scope of the Parameters they occur within, and	are unique within the scope of the Parameters they occur within, and
	the values are bare items (i.e., they themselves cannot be	the values are bare items (i.e., they themselves cannot be

	parameterized; see <xref target="item" format="default"/>).</t>	parameterized; see <xref target="item"/>).</t>
	<t>The ABNF for Parameters is:</t>	<t>The ABNF for Parameters is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	parameters = ( ";" SP parameter )	parameters = ( ";" SP parameter )
	parameter = param-name [ "=" param-value ]	parameter = param-name [ "=" param-value ]
	param-name = key	param-name = key
	key = ( lcalpha / "*" )	key = ( lcalpha / "*" )
	( lcalpha / DIGIT / "_" / "-" / "." / "" )	( lcalpha / DIGIT / "_" / "-" / "." / "" )
	lcalpha = %x61-7A ; a-z	lcalpha = %x61-7A ; a-z
	param-value = bare-item	param-value = bare-item

	]]></sourcecode>	</sourcecode>
	<t>Note that Parameters are ordered as serialized, and Parameter	<t>Note that parameters are ordered as serialized, and parameter
	keys cannot contain uppercase letters. A parameter is separated from	keys cannot contain uppercase letters. A parameter is separated from
	its Item or Inner List and other parameters by a semicolon. For	its Item or Inner List and other parameters by a semicolon. For
	example:</t>	example:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-ParamList: abc;a=1;b=2; cde_456, (ghi;jk=4 l);q="9";r=w	Example-List: abc;a=1;b=2; cde_456, (ghi;jk=4 l);q="9";r=w
	]]></sourcecode>	</sourcecode>
	<t>Parameters whose value is Boolean (see <xref target="boolean"	<t>Parameters whose value is Boolean (see <xref target="boolean"/>) tr
	format="default"/>) true <bcp14>MUST</bcp14> omit that value when seria	ue <bcp14>MUST</bcp14> omit that value when serialized. For
	lized. For
	example, the "a" parameter here is true, while the "b" parameter is	example, the "a" parameter here is true, while the "b" parameter is
	false:</t>	false:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-Int: 1; a; b=?0	Example-Integer: 1; a; b=?0
	]]></sourcecode>	</sourcecode>
	<t>Note that this requirement is only on serialization; parsers are	<t>Note that this requirement is only on serialization; parsers are
	still required to correctly handle the true value when it appears in	still required to correctly handle the true value when it appears in
	a parameter.</t>	a parameter.</t>
	<t>Parsers <bcp14>MUST</bcp14> support at least 256 parameters on an I tem or Inner	<t>Parsers <bcp14>MUST</bcp14> support at least 256 parameters on an I tem or Inner

	List and support parameter keys with at least 64 characters. Field	List, and support parameter keys with at least 64 characters. Field
	specifications can constrain the order of individual Parameters, as	specifications can constrain the order of individual parameters, as
	well as their values' types as required.</t>	well as their values' types as required.</t>
	</section>	</section>
	</section>	</section>

	<section anchor="dictionary" numbered="true" toc="default">	<section anchor="dictionary">
	<name>Dictionaries</name>	<name>Dictionaries</name>
	<t>Dictionaries are ordered maps of name-value pairs, where the names	<t>Dictionaries are ordered maps of name-value pairs, where the names

	are short textual strings and the values are Items (<xref	are short textual strings and the values are Items (<xref target="item"/>
	target="item" format="default"/>) or arrays of Items, both of which	) or arrays of Items, both of which
	can be Parameterized (<xref target="param" format="default"/>). There	can be Parameterized (<xref target="param"/>). There
	can be zero or more members, and their names are unique in the scope	can be zero or more members, and their names are unique in the scope
	of the Dictionary they occur within.</t>	of the Dictionary they occur within.</t>
	<t>Implementations <bcp14>MUST</bcp14> provide access to Dictionaries bo th by index	<t>Implementations <bcp14>MUST</bcp14> provide access to Dictionaries bo th by index
	and by name. Specifications <bcp14>MAY</bcp14> use either means of access ing the	and by name. Specifications <bcp14>MAY</bcp14> use either means of access ing the
	members.</t>	members.</t>
	<t>The ABNF for Dictionaries is:</t>	<t>The ABNF for Dictionaries is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-dictionary = dict-member *( OWS "," OWS dict-member )	sf-dictionary = dict-member *( OWS "," OWS dict-member )

	dict-member = member-name [ "=" member-value ]	dict-member = member-name ( parameters / ( "=" member-value ))
	member-name = key	member-name = key
	member-value = sf-item / inner-list	member-value = sf-item / inner-list

	]]></sourcecode>	</sourcecode>
	<t>Members are ordered as serialized and separated by a comma with	<t>Members are ordered as serialized and separated by a comma with
	optional whitespace. Member names cannot contain uppercase	optional whitespace. Member names cannot contain uppercase
	characters. Names and values are separated by "=" (without	characters. Names and values are separated by "=" (without
	whitespace). For example:</t>	whitespace). For example:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-Dict: en="Applepie", da=:w4ZibGV0w6ZydGU=:	Example-Dict: en="Applepie", da=:w4ZibGV0w6ZydGU=:

	]]></sourcecode>	</sourcecode>
	<t>Note that in this example, the final "=" is due to the inclusion of	<t>Note that in this example, the final "=" is due to the inclusion of

	a Byte Sequence; see <xref target="binary" format="default"/>.</t>	a Byte Sequence; see <xref target="binary"/>.</t>
	<t>Members whose value is Boolean (see <xref target="boolean"	<t>Members whose value is Boolean (see <xref target="boolean"/>) true <b
	format="default"/>) true <bcp14>MUST</bcp14> omit that value when seriali	cp14>MUST</bcp14> omit that value when serialized. For
	zed. For
	example, here both "b" and "c" are true:</t>	example, here both "b" and "c" are true:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-Dict: a=?0, b, c; foo=bar	Example-Dict: a=?0, b, c; foo=bar

	]]></sourcecode>	</sourcecode>
	<t>Note that this requirement is only on serialization; parsers are	<t>Note that this requirement is only on serialization; parsers are
	still required to correctly handle the true Boolean value when it	still required to correctly handle the true Boolean value when it
	appears in Dictionary values.</t>	appears in Dictionary values.</t>
	<t>A Dictionary with a member whose value is an Inner List of Tokens:</t >	<t>A Dictionary with a member whose value is an Inner List of Tokens:</t >

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-DictList: rating=1.5, feelings=(joy sadness)	Example-Dict: rating=1.5, feelings=(joy sadness)
	]]></sourcecode>	</sourcecode>
	<t>A Dictionary with a mix of Items and Inner Lists, some with Parameter	<t>A Dictionary with a mix of Items and Inner Lists, some with parameter
	s:</t>	s:</t>
	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-MixDict: a=(1 2), b=3, c=4;aa=bb, d=(5 6);valid	Example-Dict: a=(1 2), b=3, c=4;aa=bb, d=(5 6);valid
	]]></sourcecode>	</sourcecode>
	<t>As with Lists, an empty Dictionary is represented by omitting the	<t>As with Lists, an empty Dictionary is represented by omitting the
	entire field. This implies that fields defined as Dictionaries have a	entire field. This implies that fields defined as Dictionaries have a
	default empty value.</t>	default empty value.</t>
	<t>Typically, a field specification will define the semantics of	<t>Typically, a field specification will define the semantics of
	Dictionaries by specifying the allowed type(s) for individual members	Dictionaries by specifying the allowed type(s) for individual members
	by their names, as well as whether their presence is required or	by their names, as well as whether their presence is required or
	optional. Recipients <bcp14>MUST</bcp14> ignore names that are undefined or unknown,	optional. Recipients <bcp14>MUST</bcp14> ignore names that are undefined or unknown,
	unless the field's specification specifically disallows them.</t>	unless the field's specification specifically disallows them.</t>
	<t>Note that Dictionaries can have their members split across multiple	<t>Note that Dictionaries can have their members split across multiple
	lines inside a header or trailer section; for example, the following	lines inside a header or trailer section; for example, the following
	are equivalent:</t>	are equivalent:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-Hdr: foo=1, bar=2	Example-Dict: foo=1, bar=2
	]]></sourcecode>	</sourcecode>
	<t>and</t>	<t>and</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-Hdr: foo=1	Example-Dict: foo=1
	Example-Hdr: bar=2	Example-Dict: bar=2
	]]></sourcecode>	</sourcecode>
	<t>However, individual members of a Dictionary cannot be safely split	<t>However, individual members of a Dictionary cannot be safely split

	between lines; see <xref target="text-parse" format="default"/> for	between lines; see <xref target="text-parse"/> for
	details.</t>	details.</t>
	<t>Parsers <bcp14>MUST</bcp14> support Dictionaries containing at least 1024	<t>Parsers <bcp14>MUST</bcp14> support Dictionaries containing at least 1024
	name/value pairs and names with at least 64 characters. Field	name/value pairs and names with at least 64 characters. Field
	specifications can constrain the order of individual Dictionary	specifications can constrain the order of individual Dictionary
	members, as well as their values' types as required.</t>	members, as well as their values' types as required.</t>
	</section>	</section>

	<section anchor="item" numbered="true" toc="default">	<section anchor="item">
	<name>Items</name>	<name>Items</name>

	<t>An Item can be an Integer (<xref target="integer"	<t>An Item can be an Integer (<xref target="integer"/>), a Decimal (<xre
	format="default"/>), a Decimal (<xref target="decimal"	f target="decimal"/>), a String (<xref target="string"/>), a Token (<xref target
	format="default"/>), a String (<xref target="string"	="token"/>),
	format="default"/>), a Token (<xref target="token" format="default"/>),	a Byte Sequence (<xref target="binary"/>), or a Boolean
	a Byte Sequence (<xref target="binary" format="default"/>), or a Boolean	(<xref target="boolean"/>). It can have associated
	(<xref target="boolean" format="default"/>). It can have associated	parameters (<xref target="param"/>).</t>
	Parameters (<xref target="param" format="default"/>).</t>
	<t>The ABNF for Items is:</t>	<t>The ABNF for Items is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-item = bare-item parameters	sf-item = bare-item parameters
	bare-item = sf-integer / sf-decimal / sf-string / sf-token	bare-item = sf-integer / sf-decimal / sf-string / sf-token
	/ sf-binary / sf-boolean	/ sf-binary / sf-boolean

	]]></sourcecode>	</sourcecode>
	<t>For example, a header field that is defined to be an Item that is	<t>For example, a header field that is defined to be an Item that is
	an Integer might look like:</t>	an Integer might look like:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-IntItemHeader: 5	Example-Integer: 5
	]]></sourcecode>	</sourcecode>
	<t>or with Parameters:</t>	<t>or with parameters:</t>
	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-IntItem: 5; foo=bar	Example-Integer: 5; foo=bar
	]]></sourcecode>	</sourcecode>
	<section anchor="integer" numbered="true" toc="default">	<section anchor="integer">
	<name>Integers</name>	<name>Integers</name>
	<t>Integers have a range of -999,999,999,999,999 to	<t>Integers have a range of -999,999,999,999,999 to
	999,999,999,999,999 inclusive (i.e., up to fifteen digits, signed),	999,999,999,999,999 inclusive (i.e., up to fifteen digits, signed),

	for IEEE 754 compatibility <xref target="IEEE754"	for IEEE 754 compatibility <xref target="IEEE754"/>.</t>
	format="default"/>.</t>
	<t>The ABNF for Integers is:</t>	<t>The ABNF for Integers is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-integer = ["-"] 1*15DIGIT	sf-integer = ["-"] 1*15DIGIT

	]]></sourcecode>	</sourcecode>
	<t>For example:</t>	<t>For example:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-Integer: 42	Example-Integer: 42

	]]></sourcecode>	</sourcecode>
	<t>Integers larger than 15 digits can be supported in a variety of	<t>Integers larger than 15 digits can be supported in a variety of

	ways; for example, by using a String (<xref target="string"	ways; for example, by using a String (<xref target="string"/>), a Byte
	format="default"/>), a Byte Sequence (<xref target="binary"	Sequence (<xref target="binary"/>), or a parameter on an Integer that acts as a
	format="default"/>), or a parameter on an Integer that acts as a
	scaling factor.</t>	scaling factor.</t>
	<t>While it is possible to serialize Integers with leading zeros	<t>While it is possible to serialize Integers with leading zeros
	(e.g., "0002", "-01") and signed zero ("-0"), these distinctions may	(e.g., "0002", "-01") and signed zero ("-0"), these distinctions may
	not be preserved by implementations.</t>	not be preserved by implementations.</t>
	<t>Note that commas in Integers are used in this section's prose	<t>Note that commas in Integers are used in this section's prose
	only for readability; they are not valid in the wire format.</t>	only for readability; they are not valid in the wire format.</t>
	</section>	</section>

	<section anchor="decimal" numbered="true" toc="default">	<section anchor="decimal">
	<name>Decimals</name>	<name>Decimals</name>
	<t>Decimals are numbers with an integer and a fractional	<t>Decimals are numbers with an integer and a fractional
	component. The integer component has at most 12 digits; the	component. The integer component has at most 12 digits; the
	fractional component has at most three digits.</t>	fractional component has at most three digits.</t>
	<t>The ABNF for decimals is:</t>	<t>The ABNF for decimals is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-decimal = ["-"] 112DIGIT "." 13DIGIT	sf-decimal = ["-"] 112DIGIT "." 13DIGIT

	]]></sourcecode>	</sourcecode>
	<t>For example, a header whose value is defined as a Decimal could	<t>For example, a header whose value is defined as a Decimal could
	look like:</t>	look like:</t>

	<sourcecode name=""><![CDATA[	<sourcecode type="http-message">
	Example-Decimal: 4.5	Example-Decimal: 4.5

	]]></sourcecode>	</sourcecode>
	<t>While it is possible to serialize Decimals with leading zeros	<t>While it is possible to serialize Decimals with leading zeros
	(e.g., "0002.5", "-01.334"), trailing zeros (e.g., "5.230",	(e.g., "0002.5", "-01.334"), trailing zeros (e.g., "5.230",
	"-0.40"), and signed zero (e.g., "-0.0"), these distinctions may not	"-0.40"), and signed zero (e.g., "-0.0"), these distinctions may not
	be preserved by implementations.</t>	be preserved by implementations.</t>

	<t>Note that the serialization algorithm (<xref target="ser-decimal"	<t>Note that the serialization algorithm (<xref target="ser-decimal"/>
	format="default"/>) rounds input with more than three digits of	) rounds input with more than three digits of
	precision in the fractional component. If an alternative rounding	precision in the fractional component. If an alternative rounding
	strategy is desired, this should be specified by the header	strategy is desired, this should be specified by the header
	definition to occur before serialization.</t>	definition to occur before serialization.</t>
	</section>	</section>

	<section anchor="string" numbered="true" toc="default">	<section anchor="string">
	<name>Strings</name>	<name>Strings</name>

	<t>Strings are zero or more printable ASCII <xref target="RFC0020"	<t>Strings are zero or more printable ASCII <xref target="RFC0020"/> c
	format="default"/> characters (i.e., the range %x20 to %x7E). Note	haracters (i.e., the range %x20 to %x7E). Note
	that this excludes tabs, newlines, carriage returns, etc.</t>	that this excludes tabs, newlines, carriage returns, etc.</t>
	<t>The ABNF for Strings is:</t>	<t>The ABNF for Strings is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-string = DQUOTE *chr DQUOTE	sf-string = DQUOTE *chr DQUOTE
	chr = unescaped / escaped	chr = unescaped / escaped
	unescaped = %x20-21 / %x23-5B / %x5D-7E	unescaped = %x20-21 / %x23-5B / %x5D-7E
	escaped = "\" ( DQUOTE / "\" )	escaped = "\" ( DQUOTE / "\" )

	]]></sourcecode>	</sourcecode>
	<t>Strings are delimited with double quotes, using a backslash ("\")	<t>Strings are delimited with double quotes, using a backslash ("\")
	to escape double quotes and backslashes. For example:</t>	to escape double quotes and backslashes. For example:</t>

	<sourcecode><![CDATA[	<sourcecode type="http-message">
	Example-String: "hello world"	Example-String: "hello world"

	]]></sourcecode>	</sourcecode>
	<t>Note that Strings only use DQUOTE as a delimiter; single quotes	<t>Note that Strings only use DQUOTE as a delimiter; single quotes
	do not delimit Strings. Furthermore, only DQUOTE and "\" can be	do not delimit Strings. Furthermore, only DQUOTE and "\" can be
	escaped; other characters after "\" <bcp14>MUST</bcp14> cause parsing t o fail.</t>	escaped; other characters after "\" <bcp14>MUST</bcp14> cause parsing t o fail.</t>
	<t>Unicode is not directly supported in Strings, because it causes a	<t>Unicode is not directly supported in Strings, because it causes a
	number of interoperability issues, and -- with few exceptions -- field	number of interoperability issues, and -- with few exceptions -- field
	values do not require it.</t>	values do not require it.</t>
	<t>When it is necessary for a field value to convey non-ASCII	<t>When it is necessary for a field value to convey non-ASCII

	content, a Byte Sequence (<xref target="binary" format="default"/>)	content, a Byte Sequence (<xref target="binary"/>)
	can be specified, along with a character encoding (preferably <xref	can be specified, along with a character encoding (preferably UTF-8 <xr
	target="RFC3629" format="default"/>).</t>	ef target="STD63"/>).</t>
	<t>Parsers <bcp14>MUST</bcp14> support Strings (after any decoding) wi th at least	<t>Parsers <bcp14>MUST</bcp14> support Strings (after any decoding) wi th at least
	1024 characters.</t>	1024 characters.</t>
	</section>	</section>

	<section anchor="token" numbered="true" toc="default">	<section anchor="token">
	<name>Tokens</name>	<name>Tokens</name>
	<t>Tokens are short textual words; their abstract model is identical	<t>Tokens are short textual words; their abstract model is identical
	to their expression in the HTTP field value serialization.</t>	to their expression in the HTTP field value serialization.</t>
	<t>The ABNF for Tokens is:</t>	<t>The ABNF for Tokens is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-token = ( ALPHA / "" ) ( tchar / ":" / "/" )	sf-token = ( ALPHA / "" ) ( tchar / ":" / "/" )

	]]></sourcecode>	</sourcecode>
	<t>For example:</t>	<t>For example:</t>

	<sourcecode><![CDATA[	<sourcecode type="http-message">
	Example-Token: foo123/456	Example-Token: foo123/456

	]]></sourcecode>	</sourcecode>
	<t>Parsers <bcp14>MUST</bcp14> support Tokens with at least 512 charac ters.</t>	<t>Parsers <bcp14>MUST</bcp14> support Tokens with at least 512 charac ters.</t>
	<t>Note that Token allows the same characters as the "token" ABNF	<t>Note that Token allows the same characters as the "token" ABNF

	rule defined in <xref target="RFC7230" format="default"/>, with the	rule defined in <xref target="RFC7230"/>, with the
	exceptions that the first character is required to be either ALPHA	exceptions that the first character is required to be either ALPHA
	or "*", and ":" and "/" are also allowed in subsequent	or "*", and ":" and "/" are also allowed in subsequent
	characters.</t>	characters.</t>
	</section>	</section>

	<section anchor="binary" numbered="true" toc="default">	<section anchor="binary">
	<name>Byte Sequences</name>	<name>Byte Sequences</name>
	<t>Byte Sequences can be conveyed in Structured Fields.</t>	<t>Byte Sequences can be conveyed in Structured Fields.</t>
	<t>The ABNF for a Byte Sequence is:</t>	<t>The ABNF for a Byte Sequence is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-binary = ":" *(base64) ":"	sf-binary = ":" *(base64) ":"
	base64 = ALPHA / DIGIT / "+" / "/" / "="	base64 = ALPHA / DIGIT / "+" / "/" / "="

	]]></sourcecode>	</sourcecode>
	<t>A Byte Sequence is delimited with colons and encoded using base64	<t>A Byte Sequence is delimited with colons and encoded using base64
	(<xref target="RFC4648" sectionFormat="comma" section="4"/>). For	(<xref target="RFC4648" sectionFormat="comma" section="4"/>). For
	example:</t>	example:</t>

	<sourcecode><![CDATA[	<sourcecode type="http-message">
	Example-Binary: :cHJldGVuZCB0aGlzIGlzIGJpbmFyeSBjb250ZW50Lg==:	Example-ByteSequence: :cHJldGVuZCB0aGlzIGlzIGJpbmFyeSBjb250ZW50Lg==:
	]]></sourcecode>	</sourcecode>

	<t>Parsers <bcp14>MUST</bcp14> support Byte Sequences with at least 16 384 octets	<t>Parsers <bcp14>MUST</bcp14> support Byte Sequences with at least 16 384 octets
	after decoding.</t>	after decoding.</t>
	</section>	</section>

	<section anchor="boolean" numbered="true" toc="default">	<section anchor="boolean">
	<name>Booleans</name>	<name>Booleans</name>
	<t>Boolean values can be conveyed in Structured Fields.</t>	<t>Boolean values can be conveyed in Structured Fields.</t>
	<t>The ABNF for a Boolean is:</t>	<t>The ABNF for a Boolean is:</t>

	<sourcecode type="abnf"><![CDATA[	<sourcecode type="abnf">
	sf-boolean = "?" boolean	sf-boolean = "?" boolean
	boolean = "0" / "1"	boolean = "0" / "1"

	]]></sourcecode>	</sourcecode>

	<t>A Boolean is indicated with a leading "?" character followed by a	<t>A Boolean is indicated with a leading "?" character followed by a
	"1" for a true value or "0" for false. For example:</t>	"1" for a true value or "0" for false. For example:</t>

	<sourcecode><![CDATA[	<sourcecode type="http-message">
	Example-Bool: ?1	Example-Boolean: ?1
	]]></sourcecode>	</sourcecode>
	<t>Note that in Dictionary (<xref target="dictionary"	<t>Note that in Dictionary (<xref target="dictionary"/>) and Parameter
	format="default"/>) and Parameter (<xref target="param"	(<xref target="param"/>) values, Boolean true is indicated by omitting
	format="default"/>) values, Boolean true is indicated by omitting
	the value.</t>	the value.</t>
	</section>	</section>
	</section>	</section>
	</section>	</section>

	<section anchor="text" numbered="true" toc="default">	<section anchor="text">
	<name>Working with Structured Fields in HTTP</name>	<name>Working with Structured Fields in HTTP</name>
	<t>This section defines how to serialize and parse Structured Fields in	<t>This section defines how to serialize and parse Structured Fields in
	textual HTTP field values and other encodings compatible with them	textual HTTP field values and other encodings compatible with them

	(e.g., in HTTP/2 <xref target="RFC7540" format="default"/> before	(e.g., in HTTP/2 <xref target="RFC7540"/> before
	compression with HPACK <xref target="RFC7541" format="default"/>).</t>	compression with HPACK <xref target="RFC7541"/>).</t>
	<section anchor="text-serialize" numbered="true" toc="default">	<section anchor="text-serialize">
	<name>Serializing Structured Fields</name>	<name>Serializing Structured Fields</name>
	<t>Given a structure defined in this specification, return an ASCII	<t>Given a structure defined in this specification, return an ASCII
	string suitable for use in an HTTP field value.</t>	string suitable for use in an HTTP field value.</t>

		<ol>
	<ol spacing="normal" type="1">
	<li>If the structure is a Dictionary or List and its value is empty	<li>If the structure is a Dictionary or List and its value is empty
	(i.e., it has no members), do not serialize the field at all (i.e.,	(i.e., it has no members), do not serialize the field at all (i.e.,
	omit both the field-name and field-value).</li>	omit both the field-name and field-value).</li>
	<li>If the structure is a List, let output_string be the result of	<li>If the structure is a List, let output_string be the result of

	running Serializing a List (<xref target="ser-list"	running Serializing a List (<xref target="ser-list"/>) with the structu
	format="default"/>) with the structure.</li>	re.</li>
	<li>Else, if the structure is a Dictionary, let output_string be the	<li>Else, if the structure is a Dictionary, let output_string be the

	result of running Serializing a Dictionary (<xref	result of running Serializing a Dictionary (<xref target="ser-dictionar
	target="ser-dictionary" format="default"/>) with the structure.</li>	y"/>) with the structure.</li>
	<li>Else, if the structure is an Item, let output_string be the	<li>Else, if the structure is an Item, let output_string be the

	result of running Serializing an Item (<xref target="ser-item"	result of running Serializing an Item (<xref target="ser-item"/>) with
	format="default"/>) with the structure.</li>	the structure.</li>
	<li>Else, fail serialization.</li>	<li>Else, fail serialization.</li>
	<li>Return output_string converted into an array of bytes, using	<li>Return output_string converted into an array of bytes, using

	ASCII encoding <xref target="RFC0020" format="default"/>.</li>	ASCII encoding <xref target="RFC0020"/>.</li>
	</ol>	</ol>

		<section anchor="ser-list">
	<section anchor="ser-list" numbered="true" toc="default">
	<name>Serializing a List</name>	<name>Serializing a List</name>
	<t>Given an array of (member_value, parameters) tuples as	<t>Given an array of (member_value, parameters) tuples as
	input_list, return an ASCII string suitable for use in an HTTP field	input_list, return an ASCII string suitable for use in an HTTP field
	value.</t>	value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>	<li>
	<t>For each (member_value, parameters) of input_list:	<t>For each (member_value, parameters) of input_list:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If member_value is an array, append the result of running	<li>If member_value is an array, append the result of running

	Serializing an Inner List (<xref target="ser-innerlist"	Serializing an Inner List (<xref target="ser-innerlist"/>) with (
	format="default"/>) with (member_value, parameters) to	member_value, parameters) to
	output.</li>	output.</li>
	<li>Otherwise, append the result of running Serializing an	<li>Otherwise, append the result of running Serializing an

	Item (<xref target="ser-item" format="default"/>) with	Item (<xref target="ser-item"/>) with
	(member_value, parameters) to output.</li>	(member_value, parameters) to output.</li>
	<li>	<li>
	<t>If more member_values remain in input_list:	<t>If more member_values remain in input_list:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append "," to output.</li>	<li>Append "," to output.</li>
	<li>Append a single SP to output.</li>	<li>Append a single SP to output.</li>
	</ol>	</ol>
	</li>	</li>
	</ol>	</ol>
	</li>	</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>

	<section anchor="ser-innerlist" numbered="true" toc="default">	<section anchor="ser-innerlist">
	<name>Serializing an Inner List</name>	<name>Serializing an Inner List</name>
	<t>Given an array of (member_value, parameters) tuples as	<t>Given an array of (member_value, parameters) tuples as
	inner_list, and parameters as list_parameters, return an ASCII	inner_list, and parameters as list_parameters, return an ASCII
	string suitable for use in an HTTP field value.</t>	string suitable for use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let output be the string "(".</li>	<li>Let output be the string "(".</li>
	<li>	<li>
	<t>For each (member_value, parameters) of inner_list:	<t>For each (member_value, parameters) of inner_list:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append the result of running Serializing an Item (<xref	<li>Append the result of running Serializing an Item (<xref ta
	target="ser-item" format="default"/>) with (member_value,	rget="ser-item"/>) with (member_value,
	parameters) to output.</li>	parameters) to output.</li>
	<li>If more values remain in inner_list, append a single SP to output.</li>	<li>If more values remain in inner_list, append a single SP to output.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Append ")" to output.</li>	<li>Append ")" to output.</li>

	<li>Append the result of running Serializing Parameters (<xref	<li>Append the result of running Serializing Parameters (<xref tar
	target="ser-params" format="default"/>) with list_parameters to	get="ser-params"/>) with list_parameters to
	output.</li>	output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="ser-params" numbered="true" toc="default">	<section anchor="ser-params">
	<name>Serializing Parameters</name>	<name>Serializing Parameters</name>
	<t>Given an ordered Dictionary as input_parameters (each member	<t>Given an ordered Dictionary as input_parameters (each member
	having a param_name and a param_value), return an ASCII string	having a param_name and a param_value), return an ASCII string
	suitable for use in an HTTP field value.</t>	suitable for use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>	<li>
	<t>For each param_name with a value of param_value in input_para meters:	<t>For each param_name with a value of param_value in input_para meters:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append ";" to output.</li>	<li>Append ";" to output.</li>

	<li>Append the result of running Serializing a Key (<xref	<li>Append the result of running Serializing a Key (<xref targ
	target="ser-key" format="default"/>) with param_name to	et="ser-key"/>) with param_name to
	output.</li>	output.</li>
	<li>	<li>
	<t>If param_value is not Boolean true:	<t>If param_value is not Boolean true:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append "=" to output.</li>	<li>Append "=" to output.</li>
	<li>Append the result of running Serializing a bare Item	<li>Append the result of running Serializing a bare Item

	(<xref target="ser-bare-item" format="default"/>) with	(<xref target="ser-bare-item"/>) with
	param_value to output.</li>	param_value to output.</li>
	</ol>	</ol>
	</li>	</li>
	</ol>	</ol>
	</li>	</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="ser-key" numbered="true" toc="default">	<section anchor="ser-key">
	<name>Serializing a Key</name>	<name>Serializing a Key</name>
	<t>Given a key as input_key, return an ASCII string suitable for	<t>Given a key as input_key, return an ASCII string suitable for
	use in an HTTP field value.</t>	use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Convert input_key into a sequence of ASCII characters; if	<li>Convert input_key into a sequence of ASCII characters; if
	conversion fails, fail serialization.</li>	conversion fails, fail serialization.</li>
	<li>If input_key contains characters not in lcalpha, DIGIT, "_",	<li>If input_key contains characters not in lcalpha, DIGIT, "_",
	"-", ".", or "*", fail serialization.</li>	"-", ".", or "*", fail serialization.</li>
	<li>If the first character of input_key is not lcalpha or "*",	<li>If the first character of input_key is not lcalpha or "*",
	fail serialization.</li>	fail serialization.</li>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>Append input_key to output.</li>	<li>Append input_key to output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>
	</section>	</section>

	<section anchor="ser-dictionary" numbered="true" toc="default">	<section anchor="ser-dictionary">
	<name>Serializing a Dictionary</name>	<name>Serializing a Dictionary</name>
	<t>Given an ordered Dictionary as input_dictionary (each member	<t>Given an ordered Dictionary as input_dictionary (each member
	having a member_name and a tuple value of (member_value,	having a member_name and a tuple value of (member_value,
	parameters)), return an ASCII string suitable for use in an HTTP	parameters)), return an ASCII string suitable for use in an HTTP
	field value.</t>	field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>	<li>
	<t>For each member_name with a value of (member_value, parameters) in input_dictionary:	<t>For each member_name with a value of (member_value, parameters) in input_dictionary:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append the result of running Serializing a Key (<xref	<li>Append the result of running Serializing a Key (<xref target
	target="ser-key" format="default"/>) with member's member_name	="ser-key"/>) with member's member_name
	to output.</li>	to output.</li>
	<li>	<li>
	<t>If member_value is Boolean true:	<t>If member_value is Boolean true:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append the result of running Serializing Parameters	<li>Append the result of running Serializing Parameters

	(<xref target="ser-params" format="default"/>) with	(<xref target="ser-params"/>) with
	parameters to output.</li>	parameters to output.</li>
	</ol>	</ol>
	</li>	</li>
	<li>	<li>
	<t>Otherwise:	<t>Otherwise:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append "=" to output.</li>	<li>Append "=" to output.</li>
	<li>If member_value is an array, append the result of	<li>If member_value is an array, append the result of

	running Serializing an Inner List (<xref	running Serializing an Inner List (<xref target="ser-innerlis
	target="ser-innerlist" format="default"/>) with	t"/>) with
	(member_value, parameters) to output.</li>	(member_value, parameters) to output.</li>
	<li>Otherwise, append the result of running Serializing an	<li>Otherwise, append the result of running Serializing an

	Item (<xref target="ser-item" format="default"/>) with	Item (<xref target="ser-item"/>) with
	(member_value, parameters) to output.</li>	(member_value, parameters) to output.</li>
	</ol>	</ol>
	</li>	</li>
	<li>	<li>
	<t>If more members remain in input_dictionary:	<t>If more members remain in input_dictionary:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append "," to output.</li>	<li>Append "," to output.</li>
	<li>Append a single SP to output.</li>	<li>Append a single SP to output.</li>
	</ol>	</ol>
	</li>	</li>
	</ol>	</ol>
	</li>	</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="ser-item" numbered="true" toc="default">	<section anchor="ser-item">
	<name>Serializing an Item</name>	<name>Serializing an Item</name>
	<t>Given an Item as bare_item and Parameters as item_parameters,	<t>Given an Item as bare_item and Parameters as item_parameters,
	return an ASCII string suitable for use in an HTTP field value.</t>	return an ASCII string suitable for use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>

	<li>Append the result of running Serializing a Bare Item (<xref	<li>Append the result of running Serializing a Bare Item (<xref targ
	target="ser-bare-item" format="default"/>) with bare_item to	et="ser-bare-item"/>) with bare_item to
	output.</li>	output.</li>

	<li>Append the result of running Serializing Parameters (<xref	<li>Append the result of running Serializing Parameters (<xref targe
	target="ser-params" format="default"/>) with item_parameters to	t="ser-params"/>) with item_parameters to
	output.</li>	output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>

	<section anchor="ser-bare-item" numbered="true" toc="default">	<section anchor="ser-bare-item">
	<name>Serializing a Bare Item</name>	<name>Serializing a Bare Item</name>
	<t>Given an Item as input_item, return an ASCII string suitable	<t>Given an Item as input_item, return an ASCII string suitable
	for use in an HTTP field value.</t>	for use in an HTTP field value.</t>

		<ol>
	<!--[rfced] Would you like to switch the order of #5 and #6 so that
	the section references will be in asending order?

	Original:
	5. If input_item is a Boolean, return the result of running
	Serializing a Boolean (Section 4.1.9) with input_item.

	6. If input_item is a Byte Sequence, return the result of running
	Serializing a Byte Sequence (Section 4.1.8) with input_item.

	Perhaps:

	5. If input_item is a Byte Sequence, return the result of running
	Serializing a Byte Sequence (Section 4.1.8) with input_item.

	6. If input_item is a Boolean, return the result of running
	Serializing a Boolean (Section 4.1.9) with input_item.

	<ol spacing="normal" type="1">
	<li>If input_item is an Integer, return the result of running	<li>If input_item is an Integer, return the result of running

	Serializing an Integer (<xref target="ser-integer"	Serializing an Integer (<xref target="ser-integer"/>) with input_it
	format="default"/>) with input_item.</li>	em.</li>
	<li>If input_item is a Decimal, return the result of running	<li>If input_item is a Decimal, return the result of running

	Serializing a Decimal (<xref target="ser-decimal"	Serializing a Decimal (<xref target="ser-decimal"/>) with input_ite
	format="default"/>) with input_item.</li>	m.</li>
	<li>If input_item is a String, return the result of running	<li>If input_item is a String, return the result of running

	Serializing a String (<xref target="ser-string"	Serializing a String (<xref target="ser-string"/>) with input_item.
	format="default"/>) with input_item.</li>	</li>
	<li>If input_item is a Token, return the result of running	<li>If input_item is a Token, return the result of running

	Serializing a Token (<xref target="ser-token"	Serializing a Token (<xref target="ser-token"/>) with input_item.</
	format="default"/>) with input_item.</li>	li>
	<li>If input_item is a Boolean, return the result of running
	Serializing a Boolean (<xref target="ser-boolean"
	format="default"/>) with input_item.</li>
	<li>If input_item is a Byte Sequence, return the result of	<li>If input_item is a Byte Sequence, return the result of

	running Serializing a Byte Sequence (<xref target="ser-binary"	running Serializing a Byte Sequence (<xref target="ser-binary"/>) w
	format="default"/>) with input_item.</li>	ith input_item.</li>
		<li>If input_item is a Boolean, return the result of running
		Serializing a Boolean (<xref target="ser-boolean"/>) with
		input_item.</li>
	<li>Otherwise, fail serialization.</li>	<li>Otherwise, fail serialization.</li>


	</ol>	</ol>
	</section>	</section>
	</section>	</section>

	<section anchor="ser-integer" numbered="true" toc="default">	<section anchor="ser-integer">
	<name>Serializing an Integer</name>	<name>Serializing an Integer</name>
	<t>Given an Integer as input_integer, return an ASCII string	<t>Given an Integer as input_integer, return an ASCII string
	suitable for use in an HTTP field value.</t>	suitable for use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If input_integer is not an integer in the range of	<li>If input_integer is not an integer in the range of
	-999,999,999,999,999 to 999,999,999,999,999 inclusive, fail	-999,999,999,999,999 to 999,999,999,999,999 inclusive, fail
	serialization.</li>	serialization.</li>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>If input_integer is less than (but not equal to) 0, append "-"	<li>If input_integer is less than (but not equal to) 0, append "-"
	to output.</li>	to output.</li>
	<li>Append input_integer's numeric value represented in base 10	<li>Append input_integer's numeric value represented in base 10
	using only decimal digits to output.</li>	using only decimal digits to output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="ser-decimal" numbered="true" toc="default">	<section anchor="ser-decimal">
	<name>Serializing a Decimal</name>	<name>Serializing a Decimal</name>
	<t>Given a decimal number as input_decimal, return an ASCII string	<t>Given a decimal number as input_decimal, return an ASCII string
	suitable for use in an HTTP field value.</t>	suitable for use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If input_decimal is not a decimal number, fail serialization.</l i>	<li>If input_decimal is not a decimal number, fail serialization.</l i>
	<li>If input_decimal has more than three significant digits to the	<li>If input_decimal has more than three significant digits to the
	right of the decimal point, round it to three decimal places,	right of the decimal point, round it to three decimal places,
	rounding the final digit to the nearest value, or to the even	rounding the final digit to the nearest value, or to the even
	value if it is equidistant.</li>	value if it is equidistant.</li>
	<li>If input_decimal has more than 12 significant digits to the	<li>If input_decimal has more than 12 significant digits to the
	left of the decimal point after rounding, fail serialization.</li>	left of the decimal point after rounding, fail serialization.</li>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>If input_decimal is less than (but not equal to) 0, append "-"	<li>If input_decimal is less than (but not equal to) 0, append "-"
	to output.</li>	to output.</li>

	skipping to change at line 931 ¶	skipping to change at line 807 ¶
	"0".</li>	"0".</li>
	<li>Append "." to output.</li>	<li>Append "." to output.</li>
	<li>If input_decimal's fractional component is zero, append "0" to	<li>If input_decimal's fractional component is zero, append "0" to
	output.</li>	output.</li>
	<li>Otherwise, append the significant digits of input_decimal's	<li>Otherwise, append the significant digits of input_decimal's
	fractional component represented in base 10 (using only decimal	fractional component represented in base 10 (using only decimal
	digits) to output.</li>	digits) to output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="ser-string" numbered="true" toc="default">	<section anchor="ser-string">
	<name>Serializing a String</name>	<name>Serializing a String</name>
	<t>Given a String as input_string, return an ASCII string suitable	<t>Given a String as input_string, return an ASCII string suitable
	for use in an HTTP field value.</t>	for use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Convert input_string into a sequence of ASCII characters; if	<li>Convert input_string into a sequence of ASCII characters; if
	conversion fails, fail serialization.</li>	conversion fails, fail serialization.</li>
	<li>If input_string contains characters in the range %x00-1f or	<li>If input_string contains characters in the range %x00-1f or
	%x7f (i.e., not in VCHAR or SP), fail serialization.</li>	%x7f (i.e., not in VCHAR or SP), fail serialization.</li>
	<li>Let output be the string DQUOTE.</li>	<li>Let output be the string DQUOTE.</li>
	<li>	<li>
	<t>For each character char in input_string:	<t>For each character char in input_string:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>	<li>
	<t>If char is "\" or DQUOTE:	<t>If char is "\" or DQUOTE:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append "\" to output.</li>	<li>Append "\" to output.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Append char to output.</li>	<li>Append char to output.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Append DQUOTE to output.</li>	<li>Append DQUOTE to output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="ser-token" numbered="true" toc="default">	<section anchor="ser-token">
	<name>Serializing a Token</name>	<name>Serializing a Token</name>
	<t>Given a Token as input_token, return an ASCII string suitable for	<t>Given a Token as input_token, return an ASCII string suitable for
	use in an HTTP field value.</t>	use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Convert input_token into a sequence of ASCII characters; if	<li>Convert input_token into a sequence of ASCII characters; if
	conversion fails, fail serialization.</li>	conversion fails, fail serialization.</li>
	<li>If the first character of input_token is not ALPHA or "*", or	<li>If the first character of input_token is not ALPHA or "*", or
	the remaining portion contains a character not in tchar, ":", or	the remaining portion contains a character not in tchar, ":", or
	"/", fail serialization.</li>	"/", fail serialization.</li>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>Append input_token to output.</li>	<li>Append input_token to output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="ser-binary" numbered="true" toc="default">	<section anchor="ser-binary">
	<name>Serializing a Byte Sequence</name>	<name>Serializing a Byte Sequence</name>
	<t>Given a Byte Sequence as input_bytes, return an ASCII string	<t>Given a Byte Sequence as input_bytes, return an ASCII string
	suitable for use in an HTTP field value.</t>	suitable for use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If input_bytes is not a sequence of bytes, fail serialization.</ li>	<li>If input_bytes is not a sequence of bytes, fail serialization.</ li>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>Append ":" to output.</li>	<li>Append ":" to output.</li>

	<li>Append the result of base64-encoding input_bytes as per <xref	<li>Append the result of base64-encoding input_bytes as per <xref ta
	target="RFC4648" sectionFormat="comma" section="4"/>, taking account	rget="RFC4648" sectionFormat="comma" section="4"/>, taking account of
	of
	the requirements below.</li>	the requirements below.</li>
	<li>Append ":" to output.</li>	<li>Append ":" to output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>

	<t>The encoded data is required to be padded with "=", as per <xref	<t>The encoded data is required to be padded with "=", as per <xref ta
	target="RFC4648" sectionFormat="comma" section="3.2"/>.</t>	rget="RFC4648" sectionFormat="comma" section="3.2"/>.</t>
	<t>Likewise, encoded data <bcp14>SHOULD</bcp14> have pad bits set to z ero, as per	<t>Likewise, encoded data <bcp14>SHOULD</bcp14> have pad bits set to z ero, as per
	<xref target="RFC4648" sectionFormat="comma" section="3.5"/>, unless it is	<xref target="RFC4648" sectionFormat="comma" section="3.5"/>, unless it is
	not possible to do so due to implementation constraints.</t>	not possible to do so due to implementation constraints.</t>
	</section>	</section>

	<section anchor="ser-boolean" numbered="true" toc="default">	<section anchor="ser-boolean">
	<name>Serializing a Boolean</name>	<name>Serializing a Boolean</name>
	<t>Given a Boolean as input_boolean, return an ASCII string suitable	<t>Given a Boolean as input_boolean, return an ASCII string suitable
	for use in an HTTP field value.</t>	for use in an HTTP field value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If input_boolean is not a boolean, fail serialization.</li>	<li>If input_boolean is not a boolean, fail serialization.</li>
	<li>Let output be an empty string.</li>	<li>Let output be an empty string.</li>
	<li>Append "?" to output.</li>	<li>Append "?" to output.</li>
	<li>If input_boolean is true, append "1" to output.</li>	<li>If input_boolean is true, append "1" to output.</li>
	<li>If input_boolean is false, append "0" to output.</li>	<li>If input_boolean is false, append "0" to output.</li>
	<li>Return output.</li>	<li>Return output.</li>
	</ol>	</ol>
	</section>	</section>
	</section>	</section>

	<section anchor="text-parse" numbered="true" toc="default">	<section anchor="text-parse">
	<name>Parsing Structured Fields</name>	<name>Parsing Structured Fields</name>
	<t>When a receiving implementation parses HTTP fields that are known	<t>When a receiving implementation parses HTTP fields that are known
	to be Structured Fields, it is important that care be taken, as there	to be Structured Fields, it is important that care be taken, as there
	are a number of edge cases that can cause interoperability or even	are a number of edge cases that can cause interoperability or even
	security problems. This section specifies the algorithm for doing	security problems. This section specifies the algorithm for doing
	so.</t>	so.</t>

		<t>Given an array of bytes as input_bytes that represent the chosen
	<!--[rfced] Please clarify if "an array of bytes input_bytes" is
	correct, or should it perhaps be "an array of bytes as
	input_bytes"?

	Original:
	Given an array of bytes input_bytes that represents the chosen
	field's field-value (which is empty if that field is not present),
	and field_type (one of "dictionary", "list", or "item"), return the
	parsed header value.

	Perhaps:
	Given an array of bytes as input_bytes that represent the chosen
	field's field-value (which is empty if that field is not present)
	and field_type (one of "dictionary", "list", or "item"), return the
	parsed header value.
	<t>Given an array of bytes input_bytes that represents the chosen
	field's field-value (which is empty if that field is not present) and	field's field-value (which is empty if that field is not present) and
	field_type (one of "dictionary", "list", or "item"), return the parsed	field_type (one of "dictionary", "list", or "item"), return the parsed
	header value.</t>	header value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Convert input_bytes into an ASCII string input_string; if	<li>Convert input_bytes into an ASCII string input_string; if
	conversion fails, fail parsing.</li>	conversion fails, fail parsing.</li>
	<li>Discard any leading SP characters from input_string.</li>	<li>Discard any leading SP characters from input_string.</li>
	<li>If field_type is "list", let output be the result of running	<li>If field_type is "list", let output be the result of running

	Parsing a List (<xref target="parse-list" format="default"/>) with	Parsing a List (<xref target="parse-list"/>) with
	input_string.</li>	input_string.</li>
	<li>If field_type is "dictionary", let output be the result of	<li>If field_type is "dictionary", let output be the result of

	running Parsing a Dictionary (<xref target="parse-dictionary"	running Parsing a Dictionary (<xref target="parse-dictionary"/>) with i
	format="default"/>) with input_string.</li>	nput_string.</li>
	<li>If field_type is "item", let output be the result of running	<li>If field_type is "item", let output be the result of running

	Parsing an Item (<xref target="parse-item" format="default"/>) with	Parsing an Item (<xref target="parse-item"/>) with
	input_string.</li>	input_string.</li>
	<li>Discard any leading SP characters from input_string.</li>	<li>Discard any leading SP characters from input_string.</li>
	<li>If input_string is not empty, fail parsing.</li>	<li>If input_string is not empty, fail parsing.</li>
	<li>Otherwise, return output.</li>	<li>Otherwise, return output.</li>
	</ol>	</ol>
	<t>When generating input_bytes, parsers <bcp14>MUST</bcp14> combine all field lines	<t>When generating input_bytes, parsers <bcp14>MUST</bcp14> combine all field lines
	in the same section (header or trailer) that case-insensitively match	in the same section (header or trailer) that case-insensitively match

	the field name into one comma-separated field-value, as per <xref	the field name into one comma-separated field-value, as per <xref target=
	target="RFC7230" sectionFormat="comma" section="3.2.2"/>; this assures th	"RFC7230" sectionFormat="comma" section="3.2.2"/>; this assures that
	at
	the entire field value is processed correctly.</t>	the entire field value is processed correctly.</t>
	<t>For Lists and Dictionaries, this has the effect of correctly	<t>For Lists and Dictionaries, this has the effect of correctly
	concatenating all of the field's lines, as long as individual members	concatenating all of the field's lines, as long as individual members
	of the top-level data structure are not split across multiple header	of the top-level data structure are not split across multiple header
	instances. The parsing algorithms for both types allow tab characters,	instances. The parsing algorithms for both types allow tab characters,
	since these might be used to combine field lines by some	since these might be used to combine field lines by some
	implementations.</t>	implementations.</t>
	<t>Strings split across multiple field lines will have unpredictable	<t>Strings split across multiple field lines will have unpredictable

	results, because a comma(s) and whitespace inserted upon combination	results, because one or more commas (with optional whitespace)
	will become part of the string output by the parser. Since	will become part of the string output by the parser. Since
	concatenation might be done by an upstream intermediary, the results	concatenation might be done by an upstream intermediary, the results
	are not under the control of the serializer or the parser, even when	are not under the control of the serializer or the parser, even when
	they are both under the control of the same party.</t>	they are both under the control of the same party.</t>
	<t>Tokens, Integers, Decimals, and Byte Sequences cannot be split	<t>Tokens, Integers, Decimals, and Byte Sequences cannot be split
	across multiple field lines because the inserted commas will cause	across multiple field lines because the inserted commas will cause
	parsing to fail.</t>	parsing to fail.</t>
	<t>Parsers <bcp14>MAY</bcp14> fail when processing a field value spread across	<t>Parsers <bcp14>MAY</bcp14> fail when processing a field value spread across
	multiple field lines, when one of those lines does not parse as that	multiple field lines, when one of those lines does not parse as that
	field. For example, a parsing handling an Example-String field that's	field. For example, a parsing handling an Example-String field that's
	defined as an sf-string is allowed to fail when processing this field	defined as an sf-string is allowed to fail when processing this field
	section:</t>	section:</t>

	<sourcecode><![CDATA[	<sourcecode type="http-message">
	Example-String: "foo	Example-String: "foo
	Example-String: bar"	Example-String: bar"

	]]></sourcecode>	</sourcecode>
	<t>If parsing fails -- including when calling another algorithm -- the	<t>If parsing fails -- including when calling another algorithm -- the
	entire field value <bcp14>MUST</bcp14> be ignored (i.e., treated as if th e field were	entire field value <bcp14>MUST</bcp14> be ignored (i.e., treated as if th e field were
	not present in the section). This is intentionally strict, to improve	not present in the section). This is intentionally strict, to improve
	interoperability and safety, and specifications referencing this	interoperability and safety, and specifications referencing this
	document are not allowed to loosen this requirement.</t>	document are not allowed to loosen this requirement.</t>
	<t>Note that this requirement does not apply to an implementation that	<t>Note that this requirement does not apply to an implementation that
	is not parsing the field; for example, an intermediary is not required	is not parsing the field; for example, an intermediary is not required
	to strip a failing field from a message before forwarding it.</t>	to strip a failing field from a message before forwarding it.</t>

	<section anchor="parse-list" numbered="true" toc="default">	<section anchor="parse-list">
	<name>Parsing a List</name>	<name>Parsing a List</name>
	<t>Given an ASCII string as input_string, return an array of	<t>Given an ASCII string as input_string, return an array of
	(item_or_inner_list, parameters) tuples. input_string is modified to	(item_or_inner_list, parameters) tuples. input_string is modified to
	remove the parsed value.</t>	remove the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let members be an empty array.</li>	<li>Let members be an empty array.</li>
	<li>	<li>
	<t>While input_string is not empty:	<t>While input_string is not empty:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Append the result of running Parsing an Item or Inner List	<li>Append the result of running Parsing an Item or Inner List

	(<xref target="parse-item-or-list" format="default"/>) with	(<xref target="parse-item-or-list"/>) with
	input_string to members.</li>	input_string to members.</li>
	<li>Discard any leading OWS characters from input_string.</li>	<li>Discard any leading OWS characters from input_string.</li>
	<li>If input_string is empty, return members.</li>	<li>If input_string is empty, return members.</li>
	<li>Consume the first character of input_string; if it is not	<li>Consume the first character of input_string; if it is not
	",", fail parsing.</li>	",", fail parsing.</li>
	<li>Discard any leading OWS characters from input_string.</li>	<li>Discard any leading OWS characters from input_string.</li>
	<li>If input_string is empty, there is a trailing comma; fail pa rsing.</li>	<li>If input_string is empty, there is a trailing comma; fail pa rsing.</li>
	</ol>	</ol>
	</li>	</li>
	<li>No structured data has been found; return members (which is empt y).</li>	<li>No structured data has been found; return members (which is empt y).</li>
	</ol>	</ol>

	<section anchor="parse-item-or-list" numbered="true" toc="default">	<section anchor="parse-item-or-list">
	<name>Parsing an Item or Inner List</name>	<name>Parsing an Item or Inner List</name>
	<t>Given an ASCII string as input_string, return the tuple	<t>Given an ASCII string as input_string, return the tuple
	(item_or_inner_list, parameters), where item_or_inner_list can be	(item_or_inner_list, parameters), where item_or_inner_list can be
	either a single bare item or an array of (bare_item, parameters)	either a single bare item or an array of (bare_item, parameters)
	tuples. input_string is modified to remove the parsed value.</t>	tuples. input_string is modified to remove the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the first character of input_string is "(", return the	<li>If the first character of input_string is "(", return the

	result of running Parsing an Inner List (<xref	result of running Parsing an Inner List (<xref target="parse-innerl
	target="parse-innerlist" format="default"/>) with	ist"/>) with
	input_string.</li>	input_string.</li>

	<li>Return the result of running Parsing an Item (<xref	<li>Return the result of running Parsing an Item (<xref target="pa
	target="parse-item" format="default"/>) with input_string.</li>	rse-item"/>) with input_string.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="parse-innerlist" numbered="true" toc="default">	<section anchor="parse-innerlist">
	<name>Parsing an Inner List</name>	<name>Parsing an Inner List</name>
	<t>Given an ASCII string as input_string, return the tuple	<t>Given an ASCII string as input_string, return the tuple
	(inner_list, parameters), where inner_list is an array of	(inner_list, parameters), where inner_list is an array of
	(bare_item, parameters) tuples. input_string is modified to remove	(bare_item, parameters) tuples. input_string is modified to remove
	the parsed value.</t>	the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Consume the first character of input_string; if it is not	<li>Consume the first character of input_string; if it is not
	"(", fail parsing.</li>	"(", fail parsing.</li>
	<li>Let inner_list be an empty array.</li>	<li>Let inner_list be an empty array.</li>
	<li>	<li>
	<t>While input_string is not empty:	<t>While input_string is not empty:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Discard any leading SP characters from input_string.</li>	<li>Discard any leading SP characters from input_string.</li>
	<li>	<li>
	<t>If the first character of input_string is ")":	<t>If the first character of input_string is ")":
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Consume the first character of input_string.</li>	<li>Consume the first character of input_string.</li>
	<li>Let parameters be the result of running Parsing	<li>Let parameters be the result of running Parsing

	Parameters (<xref target="parse-param"	Parameters (<xref target="parse-param"/>) with input_string
	format="default"/>) with input_string.</li>	.</li>
	<li>Return the tuple (inner_list, parameters).</li>	<li>Return the tuple (inner_list, parameters).</li>
	</ol>	</ol>
	</li>	</li>

	<li>Let item be the result of running Parsing an Item (<xref	<li>Let item be the result of running Parsing an Item (<xref t
	target="parse-item" format="default"/>) with	arget="parse-item"/>) with
	input_string.</li>	input_string.</li>
	<li>Append item to inner_list.</li>	<li>Append item to inner_list.</li>
	<li>If the first character of input_string is not SP or ")",	<li>If the first character of input_string is not SP or ")",
	fail parsing.</li>	fail parsing.</li>
	</ol>	</ol>
	</li>	</li>
	<li>The end of the Inner List was not found; fail parsing.</li>	<li>The end of the Inner List was not found; fail parsing.</li>
	</ol>	</ol>
	</section>	</section>
	</section>	</section>

	<section anchor="parse-dictionary" numbered="true" toc="default">	<section anchor="parse-dictionary">
	<name>Parsing a Dictionary</name>	<name>Parsing a Dictionary</name>
	<t>Given an ASCII string as input_string, return an ordered map	<t>Given an ASCII string as input_string, return an ordered map
	whose values are (item_or_inner_list, parameters)	whose values are (item_or_inner_list, parameters)
	tuples. input_string is modified to remove the parsed value.</t>	tuples. input_string is modified to remove the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let dictionary be an empty, ordered map.</li>	<li>Let dictionary be an empty, ordered map.</li>
	<li>	<li>
	<t>While input_string is not empty:	<t>While input_string is not empty:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let this_key be the result of running Parsing a Key (<xref	<li>Let this_key be the result of running Parsing a Key (<xref t
	target="parse-key" format="default"/>) with input_string.</li>	arget="parse-key"/>) with input_string.</li>
	<li>	<li>
	<t>If the first character of input_string is "=":	<t>If the first character of input_string is "=":
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Consume the first character of input_string.</li>	<li>Consume the first character of input_string.</li>
	<li>Let member be the result of running Parsing an Item or	<li>Let member be the result of running Parsing an Item or

	Inner List (<xref target="parse-item-or-list"	Inner List (<xref target="parse-item-or-list"/>) with input_s
	format="default"/>) with input_string.</li>	tring.</li>
	</ol>	</ol>
	</li>	</li>
	<li>	<li>
	<t>Otherwise:	<t>Otherwise:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let value be Boolean true.</li>	<li>Let value be Boolean true.</li>
	<li>Let parameters be the result of running Parsing	<li>Let parameters be the result of running Parsing

	Parameters (<xref target="parse-param" format="default"/>)	Parameters (<xref target="parse-param"/>)
	with input_string.</li>	with input_string.</li>
	<li>Let member be the tuple (value, parameters).</li>	<li>Let member be the tuple (value, parameters).</li>
	</ol>	</ol>
	</li>	</li>

	<!--[rfced] May we either add quote marks around "this_key" or delete
	"name" in the sentence below? Note that there is one other instance in the text.

	Original:
	4. Add name this_key with value member to dictionary. If
	dictionary already contains a name this_key (comparing
	character-for-character), overwrite its value.

	Perhaps:
	A) 4. Add name "this_key" with value member to dictionary. If
	dictionary already contains a name "this_key" (comparing
	character-for-character), overwrite its value.
	or

	B) 4. Add this_key with value member to dictionary. If
	dictionary already contains this_key (comparing
	character-for-character), overwrite its value.

	Another instance:

	If parameters already contains a name param_name (comparing
	character-for-character), overwrite its value.

	<li>Add name this_key with value member to dictionary. If	<li>Add name this_key with value member to dictionary. If
	dictionary already contains a name this_key (comparing	dictionary already contains a name this_key (comparing
	character for character), overwrite its value.</li>	character for character), overwrite its value.</li>
	<li>Discard any leading OWS characters from input_string.</li>	<li>Discard any leading OWS characters from input_string.</li>
	<li>If input_string is empty, return dictionary.</li>	<li>If input_string is empty, return dictionary.</li>
	<li>Consume the first character of input_string; if it is not	<li>Consume the first character of input_string; if it is not
	",", fail parsing.</li>	",", fail parsing.</li>
	<li>Discard any leading OWS characters from input_string.</li>	<li>Discard any leading OWS characters from input_string.</li>
	<li>If input_string is empty, there is a trailing comma; fail pa rsing.</li>	<li>If input_string is empty, there is a trailing comma; fail pa rsing.</li>
	</ol>	</ol>
	</li>	</li>
	<li>No structured data has been found; return dictionary (which is e mpty).</li>	<li>No structured data has been found; return dictionary (which is e mpty).</li>
	</ol>	</ol>

	<!-- [rfced] Is specifying "has the effect" important"? We wonder whether	<t>Note that when duplicate Dictionary keys are encountered, all but
	this sentence would be more clear if it were "all but the last instance are	the last instance are ignored.</t>
	ignored". (Note: this sentece appearas in Sections 4.2.2 and 4.2.3.2.)

	Original:
	Note that when duplicate Dictionary keys are encountered, this has
	the effect of ignoring all but the last instance.

	<t>Note that when duplicate Dictionary keys are encountered, it
	has the effect of ignoring all but the last instance.</t>
	</section>	</section>

	<section anchor="parse-item" numbered="true" toc="default">	<section anchor="parse-item">
	<name>Parsing an Item</name>	<name>Parsing an Item</name>
	<t>Given an ASCII string as input_string, return a (bare_item,	<t>Given an ASCII string as input_string, return a (bare_item,
	parameters) tuple. input_string is modified to remove the parsed	parameters) tuple. input_string is modified to remove the parsed
	value.</t>	value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let bare_item be the result of running Parsing a Bare Item	<li>Let bare_item be the result of running Parsing a Bare Item

	(<xref target="parse-bare-item" format="default"/>) with	(<xref target="parse-bare-item"/>) with
	input_string.</li>	input_string.</li>
	<li>Let parameters be the result of running Parsing Parameters	<li>Let parameters be the result of running Parsing Parameters

	(<xref target="parse-param" format="default"/>) with	(<xref target="parse-param"/>) with
	input_string.</li>	input_string.</li>
	<li>Return the tuple (bare_item, parameters).</li>	<li>Return the tuple (bare_item, parameters).</li>
	</ol>	</ol>

	<section anchor="parse-bare-item" numbered="true" toc="default">	<section anchor="parse-bare-item">
	<name>Parsing a Bare Item</name>	<name>Parsing a Bare Item</name>
	<t>Given an ASCII string as input_string, return a bare	<t>Given an ASCII string as input_string, return a bare
	Item. input_string is modified to remove the parsed value.</t>	Item. input_string is modified to remove the parsed value.</t>

		<ol>
	<!--[rfced] Would you like to move #5 up in the list so that the
	section mentions will be in ascending order?

	Original:
	2. If the first character of input_string is a DQUOTE, return the
	result of running Parsing a String (Section 4.2.5) with
	input_string.

	3. If the first character of input_string is ":", return the result
	of running Parsing a Byte Sequence (Section 4.2.7) with
	input_string.

	4. If the first character of input_string is "?", return the result
	of running Parsing a Boolean (Section 4.2.8) with input_string.

	5. If the first character of input_string is an ALPHA or "*", return
	the result of running Parsing a Token (Section 4.2.6) with
	input_string.

	Perhaps:
	2. If the first character of input_string is a DQUOTE, return the
	result of running Parsing a String (Section 4.2.5) with
	input_string.

	3. If the first character of input_string is an ALPHA or "*", return
	the result of running Parsing a Token (Section 4.2.6) with
	input_string.

	4. If the first character of input_string is ":", return the result
	of running Parsing a Byte Sequence (Section 4.2.7) with
	input_string.

	5. If the first character of input_string is "?", return the result
	of running Parsing a Boolean (Section 4.2.8) with input_string.

	<ol spacing="normal" type="1">
	<li>If the first character of input_string is a "-" or a DIGIT,	<li>If the first character of input_string is a "-" or a DIGIT,
	return the result of running Parsing an Integer or Decimal	return the result of running Parsing an Integer or Decimal

	(<xref target="parse-number" format="default"/>) with	(<xref target="parse-number"/>) with
	input_string.</li>	input_string.</li>
	<li>If the first character of input_string is a DQUOTE, return	<li>If the first character of input_string is a DQUOTE, return

	the result of running Parsing a String (<xref	the result of running Parsing a String (<xref target="parse-string"
	target="parse-string" format="default"/>) with	/>) with
	input_string.</li>	input_string.</li>

		<li>If the first character of input_string is an ALPHA or "*",
		return the result of running Parsing a Token (<xref target="parse-t
		oken"/>) with input_string.</li>
	<li>If the first character of input_string is ":", return the	<li>If the first character of input_string is ":", return the

	result of running Parsing a Byte Sequence (<xref	result of running Parsing a Byte Sequence (<xref target="parse-bina
	target="parse-binary" format="default"/>) with	ry"/>) with
	input_string.</li>	input_string.</li>
	<li>If the first character of input_string is "?", return the	<li>If the first character of input_string is "?", return the

	result of running Parsing a Boolean (<xref	result of running Parsing a Boolean (<xref target="parse-boolean"/>
	target="parse-boolean" format="default"/>) with	) with
	input_string.</li>	input_string.</li>

	<li>If the first character of input_string is an ALPHA or "*",
	return the result of running Parsing a Token (<xref
	target="parse-token" format="default"/>) with input_string.</li>
	<li>Otherwise, the item type is unrecognized; fail parsing.</li>	<li>Otherwise, the item type is unrecognized; fail parsing.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="parse-param" numbered="true" toc="default">	<section anchor="parse-param">
	<name>Parsing Parameters</name>	<name>Parsing Parameters</name>
	<t>Given an ASCII string as input_string, return an ordered map	<t>Given an ASCII string as input_string, return an ordered map
	whose values are bare Items. input_string is modified to remove	whose values are bare Items. input_string is modified to remove
	the parsed value.</t>	the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let parameters be an empty, ordered map.</li>	<li>Let parameters be an empty, ordered map.</li>
	<li>	<li>
	<t>While input_string is not empty:	<t>While input_string is not empty:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the first character of input_string is not ";", exit th e loop.</li>	<li>If the first character of input_string is not ";", exit th e loop.</li>

	<li>Consume a ";" character from the beginning of input_string .</li>	<li>Consume the ";" character from the beginning of input_stri ng.</li>
	<li>Discard any leading SP characters from input_string.</li>	<li>Discard any leading SP characters from input_string.</li>
	<li>Let param_name be the result of running Parsing a Key	<li>Let param_name be the result of running Parsing a Key

	(<xref target="parse-key" format="default"/>) with	(<xref target="parse-key"/>) with
	input_string.</li>	input_string.</li>
	<li>Let param_value be Boolean true.</li>	<li>Let param_value be Boolean true.</li>
	<li>	<li>
	<t>If the first character of input_string is "=":	<t>If the first character of input_string is "=":
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Consume the "=" character at the beginning of input_st ring.</li>	<li>Consume the "=" character at the beginning of input_st ring.</li>
	<li>Let param_value be the result of running Parsing a	<li>Let param_value be the result of running Parsing a

	Bare Item (<xref target="parse-bare-item"	Bare Item (<xref target="parse-bare-item"/>) with input_str
	format="default"/>) with input_string.</li>	ing.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Append key param_name with value param_value to	<li>Append key param_name with value param_value to
	parameters. If parameters already contains a name param_name	parameters. If parameters already contains a name param_name
	(comparing character for character), overwrite its	(comparing character for character), overwrite its
	value.</li>	value.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Return parameters.</li>	<li>Return parameters.</li>
	</ol>	</ol>

	<t>Note that when duplicate Parameter keys are encountered, it	<t>Note that when duplicate parameter keys are encountered,
	has the effect of ignoring all but the last instance.</t>	all but the last instance are ignored.</t>
	</section>	</section>

	<section anchor="parse-key" numbered="true" toc="default">	<section anchor="parse-key">
	<name>Parsing a Key</name>	<name>Parsing a Key</name>
	<t>Given an ASCII string as input_string, return a	<t>Given an ASCII string as input_string, return a
	key. input_string is modified to remove the parsed value.</t>	key. input_string is modified to remove the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the first character of input_string is not lcalpha or	<li>If the first character of input_string is not lcalpha or
	"*", fail parsing.</li>	"*", fail parsing.</li>
	<li>Let output_string be an empty string.</li>	<li>Let output_string be an empty string.</li>
	<li>	<li>
	<t>While input_string is not empty:	<t>While input_string is not empty:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the first character of input_string is not one of	<li>If the first character of input_string is not one of
	lcalpha, DIGIT, "_", "-", ".", or "*", return	lcalpha, DIGIT, "_", "-", ".", or "*", return
	output_string.</li>	output_string.</li>
	<li>Let char be the result of consuming the first character of input_string.</li>	<li>Let char be the result of consuming the first character of input_string.</li>
	<li>Append char to output_string.</li>	<li>Append char to output_string.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Return output_string.</li>	<li>Return output_string.</li>
	</ol>	</ol>
	</section>	</section>
	</section>	</section>

	<section anchor="parse-number" numbered="true" toc="default">	<section anchor="parse-number">
	<name>Parsing an Integer or Decimal</name>	<name>Parsing an Integer or Decimal</name>
	<t>Given an ASCII string as input_string, return an Integer or	<t>Given an ASCII string as input_string, return an Integer or
	Decimal. input_string is modified to remove the parsed value.</t>	Decimal. input_string is modified to remove the parsed value.</t>

	<t>NOTE: This algorithm parses both Integers (<xref target="integer"	<t>NOTE: This algorithm parses both Integers (<xref target="integer"/>
	format="default"/>) and Decimals (<xref target="decimal"	) and Decimals (<xref target="decimal"/>), and returns the corresponding structu
	format="default"/>) and returns the corresponding structure.</t>	re.</t>
	<ol spacing="normal" type="1">	<ol>
	<li>Let type be "integer".</li>	<li>Let type be "integer".</li>
	<li>Let sign be 1.</li>	<li>Let sign be 1.</li>
	<li>Let input_number be an empty string.</li>	<li>Let input_number be an empty string.</li>
	<li>If the first character of input_string is "-", consume it and	<li>If the first character of input_string is "-", consume it and
	set sign to -1.</li>	set sign to -1.</li>
	<li>If input_string is empty, there is an empty integer; fail	<li>If input_string is empty, there is an empty integer; fail
	parsing.</li>	parsing.</li>
	<li>If the first character of input_string is not a DIGIT, fail	<li>If the first character of input_string is not a DIGIT, fail
	parsing.</li>	parsing.</li>
	<li>	<li>
	<t>While input_string is not empty:	<t>While input_string is not empty:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let char be the result of consuming the first character of	<li>Let char be the result of consuming the first character of
	input_string.</li>	input_string.</li>
	<li>If char is a DIGIT, append it to input_number.</li>	<li>If char is a DIGIT, append it to input_number.</li>
	<li>	<li>
	<t>Else, if type is "integer" and char is ".":	<t>Else, if type is "integer" and char is ".":
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If input_number contains more than 12 characters, fail p arsing.</li>	<li>If input_number contains more than 12 characters, fail p arsing.</li>
	<li>Otherwise, append char to input_number and set type to " decimal".</li>	<li>Otherwise, append char to input_number and set type to " decimal".</li>
	</ol>	</ol>
	</li>	</li>
	<li>Otherwise, prepend char to input_string, and exit the loop.< /li>	<li>Otherwise, prepend char to input_string, and exit the loop.< /li>
	<li>If type is "integer" and input_number contains more than	<li>If type is "integer" and input_number contains more than
	15 characters, fail parsing.</li>	15 characters, fail parsing.</li>
	<li>If type is "decimal" and input_number contains more than	<li>If type is "decimal" and input_number contains more than
	16 characters, fail parsing.</li>	16 characters, fail parsing.</li>
	</ol>	</ol>
	</li>	</li>
	<li>	<li>
	<t>If type is "integer":	<t>If type is "integer":
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Parse input_number as an integer and let output_number be	<li>Parse input_number as an integer and let output_number be
	the product of the result and sign.</li>	the product of the result and sign.</li>

	<li>If output_number is outside the range -999,999,999,999,999
	to 999,999,999,999,999 inclusive, fail parsing.</li>
	</ol>	</ol>
	</li>	</li>
	<li>	<li>
	<t>Otherwise:	<t>Otherwise:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the final character of input_number is ".", fail parsing. </li>	<li>If the final character of input_number is ".", fail parsing. </li>
	<li>If the number of characters after "." in input_number is	<li>If the number of characters after "." in input_number is
	greater than three, fail parsing.</li>	greater than three, fail parsing.</li>
	<li>Parse input_number as a decimal number and let	<li>Parse input_number as a decimal number and let
	output_number be the product of the result and sign.</li>	output_number be the product of the result and sign.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Return output_number.</li>	<li>Return output_number.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="parse-string" numbered="true" toc="default">	<section anchor="parse-string">
	<name>Parsing a String</name>	<name>Parsing a String</name>
	<t>Given an ASCII string as input_string, return an unquoted	<t>Given an ASCII string as input_string, return an unquoted
	String. input_string is modified to remove the parsed value.</t>	String. input_string is modified to remove the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let output_string be an empty string.</li>	<li>Let output_string be an empty string.</li>
	<li>If the first character of input_string is not DQUOTE, fail parsi ng.</li>	<li>If the first character of input_string is not DQUOTE, fail parsi ng.</li>
	<li>Discard the first character of input_string.</li>	<li>Discard the first character of input_string.</li>
	<li>	<li>
	<t>While input_string is not empty:	<t>While input_string is not empty:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>Let char be the result of consuming the first character of i nput_string.</li>	<li>Let char be the result of consuming the first character of i nput_string.</li>
	<li>	<li>
	<t>If char is a backslash ("\"):	<t>If char is a backslash ("\"):
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If input_string is now empty, fail parsing.</li>	<li>If input_string is now empty, fail parsing.</li>
	<li>Let next_char be the result of consuming the first	<li>Let next_char be the result of consuming the first
	character of input_string.</li>	character of input_string.</li>
	<li>If next_char is not DQUOTE or "\", fail parsing.</li>	<li>If next_char is not DQUOTE or "\", fail parsing.</li>
	<li>Append next_char to output_string.</li>	<li>Append next_char to output_string.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Else, if char is DQUOTE, return output_string.</li>	<li>Else, if char is DQUOTE, return output_string.</li>

	<li>Else, if char is in the range %x00-1f or %x7f (i.e., it's	<li>Else, if char is in the range %x00-1f or %x7f (i.e., it is
	not in VCHAR or SP), fail parsing.</li>	not in VCHAR or SP), fail parsing.</li>
	<li>Else, append char to output_string.</li>	<li>Else, append char to output_string.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Reached the end of input_string without finding a closing	<li>Reached the end of input_string without finding a closing
	DQUOTE; fail parsing.</li>	DQUOTE; fail parsing.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="parse-token" numbered="true" toc="default">	<section anchor="parse-token">
	<name>Parsing a Token</name>	<name>Parsing a Token</name>
	<t>Given an ASCII string as input_string, return a	<t>Given an ASCII string as input_string, return a
	Token. input_string is modified to remove the parsed value.</t>	Token. input_string is modified to remove the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the first character of input_string is not ALPHA or "*",	<li>If the first character of input_string is not ALPHA or "*",
	fail parsing.</li>	fail parsing.</li>
	<li>Let output_string be an empty string.</li>	<li>Let output_string be an empty string.</li>
	<li>	<li>
	<t>While input_string is not empty:	<t>While input_string is not empty:
	</t>	</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the first character of input_string is not in tchar,	<li>If the first character of input_string is not in tchar,
	":", or "/", return output_string.</li>	":", or "/", return output_string.</li>
	<li>Let char be the result of consuming the first character of	<li>Let char be the result of consuming the first character of
	input_string.</li>	input_string.</li>
	<li>Append char to output_string.</li>	<li>Append char to output_string.</li>
	</ol>	</ol>
	</li>	</li>
	<li>Return output_string.</li>	<li>Return output_string.</li>
	</ol>	</ol>
	</section>	</section>

	<section anchor="parse-binary" numbered="true" toc="default">	<section anchor="parse-binary">
	<name>Parsing a Byte Sequence</name>	<name>Parsing a Byte Sequence</name>
	<t>Given an ASCII string as input_string, return a Byte	<t>Given an ASCII string as input_string, return a Byte
	Sequence. input_string is modified to remove the parsed value.</t>	Sequence. input_string is modified to remove the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the first character of input_string is not ":", fail parsing. </li>	<li>If the first character of input_string is not ":", fail parsing. </li>
	<li>Discard the first character of input_string.</li>	<li>Discard the first character of input_string.</li>
	<li>If there is not a ":" character before the end of input_string, fail parsing.</li>	<li>If there is not a ":" character before the end of input_string, fail parsing.</li>
	<li>Let b64_content be the result of consuming content of	<li>Let b64_content be the result of consuming content of
	input_string up to but not including the first instance of the	input_string up to but not including the first instance of the
	character ":".</li>	character ":".</li>
	<li>Consume the ":" character at the beginning of input_string.</li>	<li>Consume the ":" character at the beginning of input_string.</li>
	<li>If b64_content contains a character not included in ALPHA,	<li>If b64_content contains a character not included in ALPHA,
	DIGIT, "+", "/", and "=", fail parsing.</li>	DIGIT, "+", "/", and "=", fail parsing.</li>

	<li>Let binary_content be the result of base64-decoding <xref	<li>Let binary_content be the result of base64-decoding <xref target
	target="RFC4648" format="default"/> b64_content, synthesizing	="RFC4648"/> b64_content, synthesizing
	padding if necessary (note the requirements about recipient	padding if necessary (note the requirements about recipient

	behavior below).</li>	behavior below). If base64 decoding fails, parsing fails.</li>
	<li>Return binary_content.</li>	<li>Return binary_content.</li>
	</ol>	</ol>
	<t>Because some implementations of base64 do not allow rejection of	<t>Because some implementations of base64 do not allow rejection of

	encoded data that is not properly "=" padded (see <xref	encoded data that is not properly "=" padded (see <xref target="RFC4648
	target="RFC4648" sectionFormat="comma" section="3.2"/>), parsers <bcp14	" sectionFormat="comma" section="3.2"/>), parsers <bcp14>SHOULD
	>SHOULD
	NOT</bcp14> fail when "=" padding is not present, unless they cannot be	NOT</bcp14> fail when "=" padding is not present, unless they cannot be
	configured to do so.</t>	configured to do so.</t>
	<t>Because some implementations of base64 do not allow rejection of	<t>Because some implementations of base64 do not allow rejection of

	encoded data that has non-zero pad bits (see <xref target="RFC4648"	encoded data that has non-zero pad bits (see <xref target="RFC4648" sec
	sectionFormat="comma" section="3.5"/>), parsers <bcp14>SHOULD NOT</bcp1	tionFormat="comma" section="3.5"/>), parsers <bcp14>SHOULD NOT</bcp14> fail when
	4> fail when
	non-zero pad bits are present, unless they cannot be configured to	non-zero pad bits are present, unless they cannot be configured to
	do so.</t>	do so.</t>

	<t>This specification does not relax the requirements in <xref	<t>This specification does not relax the requirements in <xref target=
	target="RFC4648"/>, Sections <xref	"RFC4648"/>, Sections <xref target="RFC4648" sectionFormat="bare" section="3.1"/
	target="RFC4648" sectionFormat="bare" section="3.1"/> and <xref	> and <xref target="RFC4648" sectionFormat="bare" section="3.3"/>; therefore,
	target="RFC4648" sectionFormat="bare" section="3.3"/>; therefore,
	parsers <bcp14>MUST</bcp14> fail on characters outside the base64 alpha bet and on line	parsers <bcp14>MUST</bcp14> fail on characters outside the base64 alpha bet and on line
	feeds in encoded data.</t>	feeds in encoded data.</t>
	</section>	</section>

	<section anchor="parse-boolean" numbered="true" toc="default">	<section anchor="parse-boolean">
	<name>Parsing a Boolean</name>	<name>Parsing a Boolean</name>
	<t>Given an ASCII string as input_string, return a	<t>Given an ASCII string as input_string, return a
	Boolean. input_string is modified to remove the parsed value.</t>	Boolean. input_string is modified to remove the parsed value.</t>

	<ol spacing="normal" type="1">	<ol>
	<li>If the first character of input_string is not "?", fail parsing. </li>	<li>If the first character of input_string is not "?", fail parsing. </li>
	<li>Discard the first character of input_string.</li>	<li>Discard the first character of input_string.</li>
	<li>If the first character of input_string matches "1", discard	<li>If the first character of input_string matches "1", discard
	the first character, and return true.</li>	the first character, and return true.</li>
	<li>If the first character of input_string matches "0", discard	<li>If the first character of input_string matches "0", discard
	the first character, and return false.</li>	the first character, and return false.</li>

	<li>If no value has matched; fail parsing.</li>	<li>No value has matched; fail parsing.</li>
	</ol>	</ol>
	</section>	</section>
	</section>	</section>
	</section>	</section>

	<section anchor="iana-considerations" numbered="true" toc="default">	<section anchor="iana-considerations">
	<name>IANA Considerations</name>	<name>IANA Considerations</name>
	<t>This document has no IANA actions.</t>	<t>This document has no IANA actions.</t>
	</section>	</section>

	<section anchor="security-considerations" numbered="true" toc="default">	<section anchor="security-considerations">
	<name>Security Considerations</name>	<name>Security Considerations</name>
	<t>The size of most types defined by Structured Fields is not limited;	<t>The size of most types defined by Structured Fields is not limited;
	as a result, extremely large fields could be an attack vector (e.g., for	as a result, extremely large fields could be an attack vector (e.g., for
	resource consumption). Most HTTP implementations limit the sizes of	resource consumption). Most HTTP implementations limit the sizes of
	individual fields as well as the overall header or trailer section size	individual fields as well as the overall header or trailer section size
	to mitigate such attacks.</t>	to mitigate such attacks.</t>
	<t>It is possible for parties with the ability to inject new HTTP fields	<t>It is possible for parties with the ability to inject new HTTP fields
	to change the meaning of a Structured Field. In some circumstances, this	to change the meaning of a Structured Field. In some circumstances, this
	will cause parsing to fail, but it is not possible to reliably fail in	will cause parsing to fail, but it is not possible to reliably fail in
	all such circumstances.</t>	all such circumstances.</t>
	</section>	</section>
	</middle>	</middle>
	<back>	<back>


	<displayreference target="RFC3629" to="UTF-8"/>

	<references>	<references>
	<name>References</name>	<name>References</name>
	<references>	<references>
	<name>Normative References</name>	<name>Normative References</name>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7230.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7230.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.2119.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.2119.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.8174.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.8174.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.5234.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.5234.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.0020.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.0020.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.4648.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.4648.xml"/>

	skipping to change at line 1608 ¶	skipping to change at line 1368 ¶
	<front>	<front>
	<title>IEEE Standard for Floating-Point Arithmetic</title>	<title>IEEE Standard for Floating-Point Arithmetic</title>
	<seriesInfo name="DOI" value="10.1109/IEEESTD.2019.8766229"/>	<seriesInfo name="DOI" value="10.1109/IEEESTD.2019.8766229"/>
	<seriesInfo name="IEEE" value="754-2019"/>	<seriesInfo name="IEEE" value="754-2019"/>
	<author>	<author>
	<organization>IEEE</organization>	<organization>IEEE</organization>
	</author>	</author>
	<date year="2019" month="July"/>	<date year="2019" month="July"/>
	</front>	</front>
	</reference>	</reference>

	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.3629.xml"/>


	<!--[rfced] RFC 3986 had no corresponding reference entry in the References	<reference anchor='STD63' target='https://www.rfc-editor.org/info/std63'>
	section. We have listed it as an informative reference. Please let us know	<front>
	this should instead be normative.	<title>UTF-8, a transformation format of ISO 10646</title>
		<author initials='F.' surname='Yergeau' fullname='F. Yergeau'><organization /></
		author>
		<date year='2003' month='November' />
		</front>
		<seriesInfo name='STD' value='63'/>
		<seriesInfo name='RFC' value='3629'/>
		</reference>


	Original:
	"foourl" contains a URI-reference (Section 4.1 of [RFC3986]). If
	its value is not a valid URI-reference, the entire header field
	MUST be ignored. If its value is a relative reference (Section 4.2
	of [RFC3986]), it MUST be resolved (Section 5 of [RFC3986]) before
	being used.
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refere
	nce.RFC.3986.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7231.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7231.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7540.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7540.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7541.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7541.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.8259.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.8259.xml"/>
	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7493.xml"/>	<xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/refer ence.RFC.7493.xml"/>
	</references>	</references>
	</references>	</references>

	<section anchor="faq" numbered="true" toc="default">	<section anchor="faq">
	<name>Frequently Asked Questions</name>	<name>Frequently Asked Questions</name>

	<section anchor="why-not-json" numbered="true" toc="default">	<section anchor="why-not-json">
	<name>Why Not JSON?</name>	<name>Why Not JSON?</name>

	<t>Earlier proposals for Structured Fields were based upon JSON <xref	<t>Earlier proposals for Structured Fields were based upon JSON <xref ta
	target="RFC8259" format="default"/>. However, constraining its use to	rget="RFC8259"/>. However, constraining its use to
	make it suitable for HTTP header fields required senders and	make it suitable for HTTP header fields required senders and
	recipients to implement specific additional handling.</t>	recipients to implement specific additional handling.</t>
	<t>For example, JSON has specification issues around large numbers and	<t>For example, JSON has specification issues around large numbers and
	objects with duplicate members. Although advice for avoiding these	objects with duplicate members. Although advice for avoiding these

	issues is available (e.g., <xref target="RFC7493" format="default"/>),	issues is available (e.g., <xref target="RFC7493"/>),
	it cannot be relied upon.</t>	it cannot be relied upon.</t>
	<t>Likewise, JSON strings are by default Unicode strings, which have a	<t>Likewise, JSON strings are by default Unicode strings, which have a
	number of potential interoperability issues (e.g., in	number of potential interoperability issues (e.g., in
	comparison). Although implementers can be advised to avoid non-ASCII	comparison). Although implementers can be advised to avoid non-ASCII
	content where unnecessary, this is difficult to enforce.</t>	content where unnecessary, this is difficult to enforce.</t>
	<t>Another example is JSON's ability to nest content to arbitrary	<t>Another example is JSON's ability to nest content to arbitrary
	depths. Since the resulting memory commitment might be unsuitable	depths. Since the resulting memory commitment might be unsuitable
	(e.g., in embedded and other limited server deployments), it's	(e.g., in embedded and other limited server deployments), it's
	necessary to limit it in some fashion; however, existing JSON	necessary to limit it in some fashion; however, existing JSON
	implementations have no such limits, and even if a limit is specified,	implementations have no such limits, and even if a limit is specified,

	skipping to change at line 1664 ¶	skipping to change at line 1420 ¶
	implementations; some deployments would fail to enforce them, thereby	implementations; some deployments would fail to enforce them, thereby
	harming interoperability. In short, if it looks like JSON, people will	harming interoperability. In short, if it looks like JSON, people will
	be tempted to use a JSON parser/serializer on field values.</t>	be tempted to use a JSON parser/serializer on field values.</t>
	<t>Since a major goal for Structured Fields is to improve	<t>Since a major goal for Structured Fields is to improve
	interoperability and simplify implementation, these concerns led to a	interoperability and simplify implementation, these concerns led to a
	format that requires a dedicated parser and serializer.</t>	format that requires a dedicated parser and serializer.</t>
	<t>Additionally, there were widely shared feelings that JSON doesn't	<t>Additionally, there were widely shared feelings that JSON doesn't
	"look right" in HTTP fields.</t>	"look right" in HTTP fields.</t>
	</section>	</section>
	</section>	</section>

	<section anchor="implementation-notes" numbered="true" toc="default">	<section anchor="implementation-notes">
	<name>Implementation Notes</name>	<name>Implementation Notes</name>
	<t>A generic implementation of this specification should expose the	<t>A generic implementation of this specification should expose the

	top-level serialize (<xref target="text-serialize" format="default"/>)	top-level serialize (<xref target="text-serialize"/>)
	and parse (<xref target="text-parse" format="default"/>) functions. They	and parse (<xref target="text-parse"/>) functions. They
	need not be functions; for example, it could be implemented as an	need not be functions; for example, it could be implemented as an
	object, with methods for each of the different top-level types.</t>	object, with methods for each of the different top-level types.</t>


	<t>For interoperability, it's important that generic implementations be	<t>For interoperability, it's important that generic implementations be

	complete and follow the algorithms closely; see <xref target="strict"	complete and follow the algorithms closely; see <xref target="strict"/>. T
	format="default"/>. To aid this, a common test suite is being maintained	o aid this, a common test suite is being maintained
	by the community at <eref brackets="angle" target="https://github.com/http wg/structured-field-tests"/>.</t>	by the community at <eref brackets="angle" target="https://github.com/http wg/structured-field-tests"/>.</t>


	<t>Implementers should note that Dictionaries and Parameters are	<t>Implementers should note that Dictionaries and Parameters are
	order-preserving maps. Some fields may not convey meaning in the	order-preserving maps. Some fields may not convey meaning in the
	ordering of these data types, but it should still be exposed so	ordering of these data types, but it should still be exposed so
	that it will be available to applications that need to use it.</t>	that it will be available to applications that need to use it.</t>


	<t>Likewise, implementations should note that it's important to preserve	<t>Likewise, implementations should note that it's important to preserve
	the distinction between Tokens and Strings. While most programming	the distinction between Tokens and Strings. While most programming
	languages have native types that map to the other types well, it may be	languages have native types that map to the other types well, it may be
	necessary to create a wrapper "token" object or use a parameter on	necessary to create a wrapper "token" object or use a parameter on
	functions to assure that these types remain separate.</t>	functions to assure that these types remain separate.</t>


	<t>The serialization algorithm is defined in a way that it is not	<t>The serialization algorithm is defined in a way that it is not

	strictly limited to the data types defined in <xref target="types"	strictly limited to the data types defined in <xref target="types"/> in ev
	format="default"/> in every case. For example, Decimals are designed to	ery case. For example, Decimals are designed to
	take broader input and round to allowed values.</t>	take broader input and round to allowed values.</t>

		<t>Implementations are allowed to limit the size of different
	<!--[rfced] May we update "allowed" to be "may" to avoid using allowed
	twice (e.g., "allowed to limit the allowed").

	Original:
	Implementations are allowed to limit the allowed size of different
	structures, subject to the minimums defined for each type.

	Perhaps:
	Implementations may limit the allowed size of different
	structures, subject to the minimums defined for each type.
	<t>Implementations are allowed to limit the allowed size of different
	structures, subject to the minimums defined for each type. When a	structures, subject to the minimums defined for each type. When a
	structure exceeds an implementation limit, that structure fails parsing	structure exceeds an implementation limit, that structure fails parsing
	or serialization.</t>	or serialization.</t>
	</section>	</section>

		<section numbered="false" anchor="acknowledgements">
	<section numbered="false" anchor="acknowledgements" toc="default">
	<name>Acknowledgements</name>	<name>Acknowledgements</name>
	<t>Many thanks to <contact fullname="Matthew Kerwin"/> for his detailed fe edback and careful	<t>Many thanks to <contact fullname="Matthew Kerwin"/> for his detailed fe edback and careful
	consideration during the development of this specification.</t>	consideration during the development of this specification.</t>

	<t>Thanks also to <contact fullname="Ian Clelland"/>, <contact	<t>Thanks also to <contact fullname="Ian Clelland"/>, <contact fullname="R
	fullname="Roy Fielding"/>, <contact fullname="Anne van Kesteren"/>,	oy Fielding"/>, <contact fullname="Anne van Kesteren"/>,
	<contact fullname="Kazuho Oku"/>, <contact fullname="Evert Pot"/>,	<contact fullname="Kazuho Oku"/>, <contact fullname="Evert Pot"/>,

	<contact fullname="Julian Reschke"/>, <contact fullname="Martin	<contact fullname="Julian Reschke"/>, <contact fullname="Martin Thom
	Thomson"/>, <contact fullname="Mike West"/>, and <contact	son"/>, <contact fullname="Mike West"/>, and <contact fullname="Jeffrey Yasskin"
	fullname="Jeffrey Yasskin"/> for their contributions.</t>	/> for their contributions.</t>
	</section>	</section>
	</back>	</back>


	<!-- [rfced] Throughout the text, the following terminology appears to
	be used inconsistently (a few examples are included below; see
	the text for more examples). Please review these occurrences and
	let us know if/how they may be made consistent.

	Bare Item vs. bare Item vs. bare item

	Integer vs. integer
	If input_item is an Integer,
	If input_integer is not an integer in the range

	Parameter vs. parameter
	If parameters already contains
	or a parameter on an Integer that
	within the scope the Parameters
	Parameter (Section 3.1.2) values
	and Parameter keys cannot
	and support parameter keys with

	Parameterized vs. parameterized
	can be parameterized with
	both of which can be Parameterized

	Structured Field vs. structured field
	An extension to a structured field can
	a major goal for Structured Fields is

	</rfc>	</rfc>

End of changes. 283 change blocks.
	649 lines changed or deleted	427 lines changed or added
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