rfc9165v1.txt		rfc9165.txt
	skipping to change at line 174 ¶		skipping to change at line 174 ¶
	1, and 2 as labels) and one for the Y dimension (using 3, 4, and 5 as		1, and 2 as labels) and one for the Y dimension (using 3, 4, and 5 as
	labels).		labels).
	2.2. String Concatenation		2.2. String Concatenation
	It is often useful to be able to compose string literals out of		It is often useful to be able to compose string literals out of
	component literals defined in different places in the specification.		component literals defined in different places in the specification.
	The .cat control identifies a string that is built from a		The .cat control identifies a string that is built from a
	concatenation of the target and the controller. The target and		concatenation of the target and the controller. The target and
	controller MUST be strings. The result of the operation has the type		controller MUST be strings. The result of the operation has the same
	of the target. The concatenation is performed on the bytes in both		type as the target. The concatenation is performed on the bytes in
	strings. If the target is a text string, the result of that		both strings. If the target is a text string, the result of that
	concatenation MUST be valid UTF-8.		concatenation MUST be valid UTF-8.
	a = "foo" .cat '		a = "foo" .cat '
	bar		bar
	baz		baz
	'		'
	; on a system where the newline is \n, is the same string as:		; on a system where the newline is \n, is the same string as:
	b = "foo\n bar\n baz\n"		b = "foo\n bar\n baz\n"
	Figure 2: An Example of Concatenation of Text and Byte Strings		Figure 2: An Example of Concatenation of Text and Byte Strings
	skipping to change at line 272 ¶		skipping to change at line 272 ¶
	There are several small issues, with the solutions given here:		There are several small issues, with the solutions given here:
	* ABNF can be used to define byte sequences as well as UTF-8 text		* ABNF can be used to define byte sequences as well as UTF-8 text
	strings interpreted as Unicode scalar sequences. This means this		strings interpreted as Unicode scalar sequences. This means this
	specification defines two control operators: .abnfb for ABNF		specification defines two control operators: .abnfb for ABNF
	denoting byte sequences and .abnf for denoting sequences of		denoting byte sequences and .abnf for denoting sequences of
	Unicode scalar values (code point) represented as UTF-8 text		Unicode scalar values (code point) represented as UTF-8 text
	strings. Both control operators can be applied to targets of		strings. Both control operators can be applied to targets of
	either string type; the ABNF is applied to the sequence of bytes		either string type; the ABNF is applied to the sequence of bytes
	in the string interpreting that as a sequence of bytes (.abnfb) or		in the string and interprets it as a sequence of bytes (.abnfb) or
	as a sequence of code points represented as an UTF-8 text string		as a sequence of code points represented as an UTF-8 text string
	(.abnf). The controller string MUST be a text string.		(.abnf). The controller string MUST be a text string.
	* ABNF defines a list of rules, not a single expression (called		* ABNF defines a list of rules, not a single expression (called
	"elements" in [RFC5234]). This is resolved by requiring the		"elements" in [RFC5234]). This is resolved by requiring the
	controller string to be one valid "element", followed by zero or		controller string to be one valid "element", followed by zero or
	more valid "rules" separated from the element by a newline; thus,		more valid "rules" separated from the element by a newline; thus,
	the controller string can be built by preceding a piece of valid		the controller string can be built by preceding a piece of valid
	ABNF by an "element" that selects from that ABNF and a newline.		ABNF by an "element" that selects from that ABNF and a newline.
	skipping to change at line 353 ¶		skipping to change at line 353 ¶
	4. Features		4. Features
	Commonly, the kind of validation enabled by languages such as CDDL		Commonly, the kind of validation enabled by languages such as CDDL
	provides a Boolean result: valid or invalid.		provides a Boolean result: valid or invalid.
	In rapidly evolving environments, this is too simplistic. The data		In rapidly evolving environments, this is too simplistic. The data
	models described by a CDDL specification may continually be enhanced		models described by a CDDL specification may continually be enhanced
	by additional features, and it would be useful even for a		by additional features, and it would be useful even for a
	specification that does not yet describe a specific future feature to		specification that does not yet describe a specific future feature to
	identify the extension point the feature can use, accepting such		identify the extension point the feature can use and accept such
	extensions while marking them as such.		extensions while marking them as such.
	The .feature control annotates the target as making use of the		The .feature control annotates the target as making use of the
	feature named by the controller. The latter will usually be a		feature named by the controller. The latter will usually be a
	string. A tool that validates an instance against that specification		string. A tool that validates an instance against that specification
	may mark the instance as using a feature that is annotated by the		may mark the instance as using a feature that is annotated by the
	specification.		specification.
	More specifically, the tool's diagnostic output might contain the		More specifically, the tool's diagnostic output might contain the
	controller (right-hand side) as a feature name and the target (left-		controller (right-hand side) as a feature name and the target (left-
End of changes. 3 change blocks.
	5 lines changed or deleted		5 lines changed or added
This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/