rfc9535v5.txt		rfc9535.txt
	skipping to change at line 134 ¶		skipping to change at line 134 ¶
	B.1. JSONPath and XPath		B.1. JSONPath and XPath
	Appendix C. JSON Pointer		Appendix C. JSON Pointer
	Acknowledgements		Acknowledgements
	Contributors		Contributors
	Authors' Addresses		Authors' Addresses
	1. Introduction		1. Introduction
	JSON [RFC8259] is a popular representation format for structured data		JSON [RFC8259] is a popular representation format for structured data
	values. JSONPath defines a string syntax for selecting and		values. JSONPath defines a string syntax for selecting and
	extracting JSON [RFC8259] values from within a given JSON value.		extracting JSON values from within a given JSON value.
	In relation to JSON Pointer [RFC6901], JSONPath is not intended as a		In relation to JSON Pointer [RFC6901], JSONPath is not intended as a
	replacement but as a more powerful companion. See Appendix C.		replacement but as a more powerful companion. See Appendix C.
	1.1. Terminology		1.1. Terminology
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in		"OPTIONAL" in this document are to be interpreted as described in
	BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all		BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
	skipping to change at line 739 ¶		skipping to change at line 739 ¶
	slice-selector /		slice-selector /
	index-selector /		index-selector /
	filter-selector		filter-selector
	The syntax and semantics of each kind of selector are defined below.		The syntax and semantics of each kind of selector are defined below.
	2.3.1. Name Selector		2.3.1. Name Selector
	2.3.1.1. Syntax		2.3.1.1. Syntax
	A name selector '<name>' selects one object member value at most.		A name selector '<name>' selects at most one object member value.
	In contrast to JSON, the JSONPath syntax allows strings to be		In contrast to JSON, the JSONPath syntax allows strings to be
	enclosed in _single_ or _double_ quotes.		enclosed in _single_ or _double_ quotes.
	name-selector = string-literal		name-selector = string-literal
	string-literal = %x22 *double-quoted %x22 / ; "string"		string-literal = %x22 *double-quoted %x22 / ; "string"
	%x27 *single-quoted %x27 ; 'string'		%x27 *single-quoted %x27 ; 'string'
	double-quoted = unescaped /		double-quoted = unescaped /
	skipping to change at line 963 ¶		skipping to change at line 963 ¶
	The example above with the query $.o[*, *] shows that the wildcard		The example above with the query $.o[*, *] shows that the wildcard
	selector may produce nodelists in distinct orders each time it		selector may produce nodelists in distinct orders each time it
	appears in the child segment when it is applied to an object node		appears in the child segment when it is applied to an object node
	with two or more members (but not when it is applied to object nodes		with two or more members (but not when it is applied to object nodes
	with fewer than two members or to array nodes).		with fewer than two members or to array nodes).
	2.3.3. Index Selector		2.3.3. Index Selector
	2.3.3.1. Syntax		2.3.3.1. Syntax
	An index selector <index> matches one array element value at most.		An index selector <index> matches at most one array element value.
	index-selector = int ; decimal integer		index-selector = int ; decimal integer
	int = "0" /		int = "0" /
	(["-"] DIGIT1 *DIGIT) ; - optional		(["-"] DIGIT1 *DIGIT) ; - optional
	DIGIT1 = %x31-39 ; 1-9 non-zero digit		DIGIT1 = %x31-39 ; 1-9 non-zero digit
	Applying the numerical index-selector selects the corresponding		Applying the numerical index-selector selects the corresponding
	element. JSONPath allows it to be negative (see Section 2.3.3.2).		element. JSONPath allows it to be negative (see Section 2.3.3.2).
	skipping to change at line 1046 ¶		skipping to change at line 1046 ¶
	The slice selector consists of three optional decimal integers		The slice selector consists of three optional decimal integers
	separated by colons. The second colon can be omitted when the third		separated by colons. The second colon can be omitted when the third
	integer is omitted.		integer is omitted.
	To be valid, the integers provided MUST be in the I-JSON range of		To be valid, the integers provided MUST be in the I-JSON range of
	exact values (see Section 2.1).		exact values (see Section 2.1).
	2.3.4.2. Semantics		2.3.4.2. Semantics
	The slice selector was inspired by the slice operator of ECMAScript 4		The slice selector was inspired by the slice operator that was
	(ES4), which was deprecated in 2014, and that of Python.		proposed for ECMAScript 4 (ES4), which was never released, and that
			of Python.
	2.3.4.2.1. Informal Introduction		2.3.4.2.1. Informal Introduction
	This section is informative.		This section is informative.
	Array slicing is inspired by the behavior of the		Array slicing is inspired by the behavior of the
	Array.prototype.slice method of the JavaScript language, as defined		Array.prototype.slice method of the JavaScript language, as defined
	by the ECMA-262 standard [ECMA-262], with the addition of the step		by the ECMA-262 standard [ECMA-262], with the addition of the step
	parameter, which is inspired by the Python slice expression.		parameter, which is inspired by the Python slice expression.
	skipping to change at line 1493 ¶		skipping to change at line 1494 ¶
	JSON:		JSON:
	{		{
	"obj": {"x": "y"},		"obj": {"x": "y"},
	"arr": [2, 3]		"arr": [2, 3]
	}		}
	Comparisons:		Comparisons:
	+========================+========+============================+		+========================+========+========================+
	| Comparison | Result | Comment |		| Comparison | Result | Comment |
	+========================+========+============================+		+========================+========+========================+
	| $.absent1 == $.absent2 | true | Empty nodelists |		| $.absent1 == $.absent2 | true | Empty nodelists |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.absent1 <= $.absent2 | true | == implies <= |		| $.absent1 <= $.absent2 | true | == implies <= |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.absent == 'g' | false | Empty nodelist |		| $.absent == 'g' | false | Empty nodelist |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.absent1 != $.absent2 | false | Empty nodelists |		| $.absent1 != $.absent2 | false | Empty nodelists |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.absent != 'g' | true | Empty nodelist |		| $.absent != 'g' | true | Empty nodelist |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 1 <= 2 | true | Numeric comparison |		| 1 <= 2 | true | Numeric comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 1 > 2 | false | Strict, numeric comparison |		| 1 > 2 | false | Numeric comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 13 == '13' | false | Type mismatch |		| 13 == '13' | false | Type mismatch |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 'a' <= 'b' | true | String comparison |		| 'a' <= 'b' | true | String comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 'a' > 'b' | false | Strict, string comparison |		| 'a' > 'b' | false | String comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj == $.arr | false | Type mismatch |		| $.obj == $.arr | false | Type mismatch |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj != $.arr | true | Type mismatch |		| $.obj != $.arr | true | Type mismatch |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj == $.obj | true | Object comparison |		| $.obj == $.obj | true | Object comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj != $.obj | false | Object comparison |		| $.obj != $.obj | false | Object comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.arr == $.arr | true | Array comparison |		| $.arr == $.arr | true | Array comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.arr != $.arr | false | Array comparison |		| $.arr != $.arr | false | Array comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj == 17 | false | Type mismatch |		| $.obj == 17 | false | Type mismatch |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj != 17 | true | Type mismatch |		| $.obj != 17 | true | Type mismatch |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj <= $.arr | false | Objects and arrays do not |		| $.obj <= $.arr | false | Objects and arrays do |
	| | | offer < comparison |		| | | not offer < comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj < $.arr | false | Objects and arrays do not |		| $.obj < $.arr | false | Objects and arrays do |
	| | | offer < comparison |		| | | not offer < comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.obj <= $.obj | true | == implies <= |		| $.obj <= $.obj | true | == implies <= |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| $.arr <= $.arr | true | == implies <= |		| $.arr <= $.arr | true | == implies <= |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 1 <= $.arr | false | Arrays do not offer < |		| 1 <= $.arr | false | Arrays do not offer < |
	| | | comparison |		| | | comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 1 >= $.arr | false | Arrays do not offer < |		| 1 >= $.arr | false | Arrays do not offer < |
	| | | comparison |		| | | comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 1 > $.arr | false | Arrays do not offer < |		| 1 > $.arr | false | Arrays do not offer < |
	| | | comparison |		| | | comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| 1 < $.arr | false | Arrays do not offer < |		| 1 < $.arr | false | Arrays do not offer < |
	| | | comparison |		| | | comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| true <= true | true | == implies <= |		| true <= true | true | == implies <= |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	| true > true | false | Booleans do not offer < |		| true > true | false | Booleans do not offer |
	| | | comparison |		| | | < comparison |
	+------------------------+--------+----------------------------+		+------------------------+--------+------------------------+
	Table 11: Comparison Examples		Table 11: Comparison Examples
	The second set of examples shows some complete JSONPath queries that		The second set of examples shows some complete JSONPath queries that
	make use of filter selectors and the results of evaluating these		make use of filter selectors and the results of evaluating these
	queries on a given JSON value as input. (Note: Two of the queries		queries on a given JSON value as input. (Note: Two of the queries
	employ function extensions; please see Sections 2.4.6 and 2.4.7 for		employ function extensions; please see Sections 2.4.6 and 2.4.7 for
	details about these.)		details about these.)
	JSON:		JSON:
	skipping to change at line 1967 ¶		skipping to change at line 1968 ¶
	$[?value(@..color) == "red"]		$[?value(@..color) == "red"]
	Its only argument is an instance of NodesType (possibly taken from a		Its only argument is an instance of NodesType (possibly taken from a
	filter-query, as in the example above). The result is an instance of		filter-query, as in the example above). The result is an instance of
	ValueType.		ValueType.
	* If the argument contains a single node, the result is the value of		* If the argument contains a single node, the result is the value of
	the node.		the node.
	* If the argument is the special result Nothing or contains multiple		* If the argument is the empty nodelist or contains multiple nodes,
	nodes, the result is Nothing.		the result is Nothing.
	Note: A singular query may be used anywhere where a ValueType is		Note: A singular query may be used anywhere where a ValueType is
	expected, so there is no need to use the value() function extension		expected, so there is no need to use the value() function extension
	with a singular query.		with a singular query.
	2.4.9. Examples		2.4.9. Examples
	+======================+==========================================+		+======================+==========================================+
	| Query | Comment |		| Query | Comment |
	+======================+==========================================+		+======================+==========================================+
	skipping to change at line 2427 ¶		skipping to change at line 2428 ¶
	+-------------+-----------------+--------------------------+		+-------------+-----------------+--------------------------+
	| $["\u0061"] | $['a'] | Unicode character |		| $["\u0061"] | $['a'] | Unicode character |
	+-------------+-----------------+--------------------------+		+-------------+-----------------+--------------------------+
	Table 18: Normalized Path Examples		Table 18: Normalized Path Examples
	3. IANA Considerations		3. IANA Considerations
	3.1. Registration of Media Type application/jsonpath		3.1. Registration of Media Type application/jsonpath
	IANA is requested to register the following media type [RFC6838]:		IANA has registered the following media type [RFC6838]:
	Type name: application		Type name: application
	Subtype name: jsonpath		Subtype name: jsonpath
	Required parameters: N/A		Required parameters: N/A
	Optional parameters: N/A		Optional parameters: N/A
	Encoding considerations: binary (UTF-8)		Encoding considerations: binary (UTF-8)
	skipping to change at line 3032 ¶		skipping to change at line 3033 ¶
	| seamless | n/a | expression engine |		| seamless | n/a | expression engine |
	+----------+------------------+-----------------------------------+		+----------+------------------+-----------------------------------+
	| () | n/a | grouping |		| () | n/a | grouping |
	+----------+------------------+-----------------------------------+		+----------+------------------+-----------------------------------+
	Table 20: XPath Syntax Compared to JSONPath		Table 20: XPath Syntax Compared to JSONPath
	For further illustration, Table 21 shows some XPath expressions and		For further illustration, Table 21 shows some XPath expressions and
	their JSONPath equivalents.		their JSONPath equivalents.
	+======================+========================+==================+		+=======================+========================+==================+
	| XPath | JSONPath | Result |		| XPath | JSONPath | Result |
	+======================+========================+==================+		+=======================+========================+==================+
	| /store/book/author | $.store.book[*].author | the authors of |		| /store/book/author | $.store.book[*].author | the authors |
	| | | all books in the |		| | | of all books |
	| | | store |		| | | in the store |
	+----------------------+------------------------+------------------+		+-----------------------+------------------------+------------------+
	| //author | $..author | all authors |		| //author | $..author | all authors |
	+----------------------+------------------------+------------------+		+-----------------------+------------------------+------------------+
	| /store/* | $.store.* | all things in |		| /store/* | $.store.* | all things in |
	| | | store, which are |		| | | store, which |
	| | | some books and a |		| | | are some |
	| | | red bicycle |		| | | books and a |
	+----------------------+------------------------+------------------+		| | | red bicycle |
	| /store//price | $.store..price | the prices of |		+-----------------------+------------------------+------------------+
	| | | everything in |		| /store//price | $.store..price | the prices of |
	| | | the store |		| | | everything in |
	+----------------------+------------------------+------------------+		| | | the store |
	| //book[3] | $..book[2] | the third book |		+-----------------------+------------------------+------------------+
	+----------------------+------------------------+------------------+		| //book[3] | $..book[2] | the third |
	| //book[last()] | $..book[-1] | the last book in |		| | | book |
	| | | order |		+-----------------------+------------------------+------------------+
	+----------------------+------------------------+------------------+		| //book[last()] | $..book[-1] | the last book |
	| //book[position()<3] | $..book[0,1] | the first two |		| | | in order |
	| | $..book[:2] | books |		+-----------------------+------------------------+------------------+
	+----------------------+------------------------+------------------+		| //book[position()<3] | $..book[0,1] | the first two |
	| //book[isbn] | $..book[?@.isbn] | filter all books |		| | $..book[:2] | books |
	| | | with an ISBN |		+-----------------------+------------------------+------------------+
	| | | number |		| //book[isbn] | $..book[?@.isbn] | filter all |
	+----------------------+------------------------+------------------+		| | | books with an |
	| //book[price<10] | $..book[?@.price<10] | filter all books |		| | | ISBN number |
	| | | cheaper than 10 |		+-----------------------+------------------------+------------------+
	+----------------------+------------------------+------------------+		| //book[price<10] | $..book[?@.price<10] | filter all |
	| //* | $..* | all elements in |		| | | books cheaper |
	| | | an XML document; |		| | | than 10 |
	| | | all member |		+-----------------------+------------------------+------------------+
	| | | values and array |		| //* | $..* | all elements |
	| | | elements |		| | | in an XML |
	| | | contained in |		| | | document; all |
	| | | input value |		| | | member values |
	+----------------------+------------------------+------------------+		| | | and array |
			| | | elements |
			| | | contained in |
			| | | input value |
			+-----------------------+------------------------+------------------+
	Table 21: Example XPath Expressions and Their JSONPath Equivalents		Table 21: Example XPath Expressions and Their JSONPath Equivalents
	XPath has a lot more functionality (location paths in unabbreviated		XPath has a lot more functionality (location paths in unabbreviated
	syntax, operators, and functions) than listed in this comparison.		syntax, operators, and functions) than listed in this comparison.
	Moreover, there are significant differences in how the subscript		Moreover, there are significant differences in how the subscript
	operator works in XPath and JSONPath:		operator works in XPath and JSONPath:
	* Square brackets in XPath expressions always operate on the _node		* Square brackets in XPath expressions always operate on the _node
	set_ resulting from the previous path fragment. Indices always		set_ resulting from the previous path fragment. Indices always
	start at 1.		start at 1.
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