133 lines
2.8 KiB
JavaScript
133 lines
2.8 KiB
JavaScript
/*
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* JSON Grammar
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* ============
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*
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* Based on the grammar from RFC 7159 [1].
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*
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* Note that JSON is also specified in ECMA-262 [2], ECMA-404 [3], and on the
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* JSON website [4] (somewhat informally). The RFC seems the most authoritative
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* source, which is confirmed e.g. by [5].
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*
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* [1] http://tools.ietf.org/html/rfc7159
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* [2] http://www.ecma-international.org/publications/standards/Ecma-262.htm
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* [3] http://www.ecma-international.org/publications/standards/Ecma-404.htm
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* [4] http://json.org/
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* [5] https://www.tbray.org/ongoing/When/201x/2014/03/05/RFC7159-JSON
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*/
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/* ----- 2. JSON Grammar ----- */
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JSON_text
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= ws value:value ws { return value; }
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begin_array = ws "[" ws
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begin_object = ws "{" ws
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end_array = ws "]" ws
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end_object = ws "}" ws
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name_separator = ws ":" ws
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value_separator = ws "," ws
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ws "whitespace" = [ \t\n\r]*
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/* ----- 3. Values ----- */
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value
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= false
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/ null
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/ true
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/ object
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/ array
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/ number
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/ string
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false = "false" { return false; }
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null = "null" { return null; }
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true = "true" { return true; }
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/* ----- 4. Objects ----- */
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object
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= begin_object
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members:(
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head:member
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tail:(value_separator m:member { return m; })*
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{
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var result = {}, i;
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result[head.name] = head.value;
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for (i = 0; i < tail.length; i++) {
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result[tail[i].name] = tail[i].value;
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}
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return result;
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}
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)?
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end_object
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{ return members !== null ? members: {}; }
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member
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= name:string name_separator value:value {
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return { name: name, value: value };
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}
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/* ----- 5. Arrays ----- */
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array
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= begin_array
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values:(
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head:value
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tail:(value_separator v:value { return v; })*
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{ return [head].concat(tail); }
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)?
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end_array
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{ return values !== null ? values : []; }
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/* ----- 6. Numbers ----- */
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number "number"
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= minus? int frac? exp? { return parseFloat(text()); }
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decimal_point = "."
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digit1_9 = [1-9]
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e = [eE]
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exp = e (minus / plus)? DIGIT+
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frac = decimal_point DIGIT+
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int = zero / (digit1_9 DIGIT*)
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minus = "-"
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plus = "+"
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zero = "0"
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/* ----- 7. Strings ----- */
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string "string"
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= quotation_mark chars:char* quotation_mark { return chars.join(""); }
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char
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= unescaped
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/ escape
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sequence:(
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'"'
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/ "\\"
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/ "/"
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/ "b" { return "\b"; }
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/ "f" { return "\f"; }
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/ "n" { return "\n"; }
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/ "r" { return "\r"; }
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/ "t" { return "\t"; }
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/ "u" digits:$(HEXDIG HEXDIG HEXDIG HEXDIG) {
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return String.fromCharCode(parseInt(digits, 16));
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}
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)
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{ return sequence; }
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escape = "\\"
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quotation_mark = '"'
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unescaped = [^\0-\x1F\x22\x5C]
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/* ----- Core ABNF Rules ----- */
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/* See RFC 4234, Appendix B (http://tools.ietf.org/html/rfc4627). */
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DIGIT = [0-9]
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HEXDIG = [0-9a-f]i
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