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acorn.js
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/
acorn.js
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// Acorn is a tiny, fast JavaScript parser written in JavaScript.
//
// Acorn was written by Marijn Haverbeke and released under an MIT
// license. The Unicode regexps (for identifiers and whitespace) were
// taken from [Esprima](http://esprima.org) by Ariya Hidayat.
//
// Git repositories for Acorn are available at
//
// http://marijnhaverbeke.nl/git/acorn
// https://github.com/marijnh/acorn.git
//
// Please use the [github bug tracker][ghbt] to report issues.
//
// [ghbt]: https://github.com/marijnh/acorn/issues
(function(exports) {
"strict mode";
exports.version = "0.0.1";
// The main exported interface (under `window.acorn` when in the
// browser) is a `parse` function that takes a code string and
// returns an abstract syntax tree as specified by [Mozilla parser
// API][api], with the caveat that the SpiderMonkey-specific syntax
// (`let`, `yield`, inline XML, etc) is not recognized.
//
// [api]: https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API
var options, input, inputLen;
exports.parse = function(inpt, opts) {
input = String(inpt); inputLen = input.length;
options = opts || {};
for (var opt in defaultOptions) if (!options.hasOwnProperty(opt))
options[opt] = defaultOptions[opt];
return parseTopLevel();
};
// A second optional argument can be given to further configure
// the parser process. These options are recognized:
var defaultOptions = exports.defaultOptions = {
// `ecmaVersion` indicates the ECMAScript version to parse. Must
// be either 3 or 5. This
// influences support for strict mode, the set of reserved words, and
// support for getters and setter.
ecmaVersion: 5,
// Turn on `strictSemicolons` to prevent the parser from doing
// automatic semicolon insertion.
strictSemicolons: false,
// When `allowTrailingCommas` is false, the parser will not allow
// trailing commas in array and object literals.
allowTrailingCommas: true,
// By default, reserved words are not enforced. Enable
// `forbidReserved` to enforce them.
forbidReserved: false,
// When `trackComments` is turned on, the parser will attach
// `commentsBefore` and `commentsAfter` properties to AST nodes
// holding arrays of strings. A single comment may appear in both
// a `commentsBefore` and `commentsAfter` array (of the nodes
// after and before it), but never twice in the before (or after)
// array of different nodes.
trackComments: false,
// When `locations` is on, `loc` properties holding objects with
// `start` and `end` properties in `{line, column}` form (with
// line being 1-based and column 0-based) will be attached to the
// nodes.
locations: false
};
// The `getLineInfo` function is mostly useful when the
// `locations` option is off (for performance reasons) and you
// want to find the line/column position for a given character
// offset. `input` should be the code string that the offset refers
// into.
var getLineInfo = exports.getLineInfo = function(input, offset) {
for (var line = 1, cur = 0;;) {
lineBreak.lastIndex = cur;
var match = lineBreak.exec(input);
if (match && match.index < offset) {
++line;
cur = match.index + match[0].length;
} else break;
}
return {line: line, column: offset - cur};
};
// Acorn is organized as a tokenizer and a recursive-descent parser.
// Both use (closure-)global variables to keep their state and
// communicate. We already saw the `options`, `input`, and
// `inputLen` variables above (set in `parse`).
// The current position of the tokenizer in the input.
var tokPos;
// The start and end offsets of the current token.
var tokStart, tokEnd;
// When `options.locations` is true, these hold objects
// containing the tokens start and end line/column pairs.
var tokStartLoc, tokEndLoc;
// The type and value of the current token. Token types are objects,
// named by variables against which they can be compared, and
// holding properties that describe them (indicating, for example,
// the precedence of an infix operator, and the original name of a
// keyword token). The kind of value that's held in `tokVal` depends
// on the type of the token. For literals, it is the literal value,
// for operators, the operator name, and so on.
var tokType, tokVal;
// These are used to hold arrays of comments when
// `options.trackComments` is true.
var tokCommentsBefore, tokCommentsAfter;
// Interal state for the tokenizer. To distinguish between division
// operators and regular expressions, it remembers whether the last
// token was one that is allowed to be followed by an expression.
// (If it is, a slash is probably a regexp, if it isn't it's a
// division operator. See the `parseStatement` function for a
// caveat.)
var tokRegexpAllowed, tokComments;
// When `options.locations` is true, these are used to keep
// track of the current line, and know when a new line has been
// entered. See the `curLineLoc` function.
var tokCurLine, tokLineStart, tokLineStartNext;
// These store the position of the previous token, which is useful
// when finishing a node and assigning its `end` position.
var lastStart, lastEnd, lastEndLoc;
// This is the parser's state. `inFunction` is used to reject
// `return` statements outside of functions, `labels` to verify that
// `break` and `continue` have somewhere to jump to, and `strict`
// indicates whether strict mode is on.
var inFunction, labels, strict;
// This function is used to raise exceptions on parse errors. It
// takes either a `{line, column}` object or an offset integer (into
// the current `input`) as `pos` argument. It attaches the position
// to the end of the error message, and then raises a `SyntaxError`
// with that message.
function raise(pos, message) {
if (typeof pos == "number") pos = getLineInfo(input, pos);
message += " (" + pos.line + ":" + pos.column + ")";
throw new SyntaxError(message);
}
// ## Token types
// The assignment of fine-grained, information-carrying type objects
// allows the tokenizer to store the information it has about a
// token in a way that is very cheap for the parser to look up.
// All token type variables start with an underscore, to make them
// easy to recognize.
// These are the general types. The `type` property is only used to
// make them recognizeable when debugging.
var _num = {type: "num"}, _regexp = {type: "regexp"}, _string = {type: "string"};
var _name = {type: "name"}, _eof = {type: "eof"};
// Keyword tokens. The `keyword` property (also used in keyword-like
// operators) indicates that the token originated from an
// identifier-like word, which is used when parsing property names.
//
// The `beforeExpr` property is used to disambiguate between regular
// expressions and divisions. It is set on all token types that can
// be followed by an expression (thus, a slash after them would be a
// regular expression).
//
// `isLoop` marks a keyword as starting a loop, which is important
// to know when parsing a label, in order to allow or disallow
// continue jumps to that label.
var _break = {keyword: "break"}, _case = {keyword: "case", beforeExpr: true}, _catch = {keyword: "catch"};
var _continue = {keyword: "continue"}, _debugger = {keyword: "debugger"}, _default = {keyword: "default"};
var _do = {keyword: "do", isLoop: true}, _else = {keyword: "else", beforeExpr: true};
var _finally = {keyword: "finally"}, _for = {keyword: "for", isLoop: true}, _function = {keyword: "function"};
var _if = {keyword: "if"}, _return = {keyword: "return", beforeExpr: true}, _switch = {keyword: "switch"};
var _throw = {keyword: "throw", beforeExpr: true}, _try = {keyword: "try"}, _var = {keyword: "var"};
var _while = {keyword: "while", isLoop: true}, _with = {keyword: "with"}, _new = {keyword: "new", beforeExpr: true};
// The keywords that denote values.
var _null = {keyword: "null", atomValue: null}, _true = {keyword: "true", atomValue: true};
var _false = {keyword: "false", atomValue: false};
// Some keywords are treated as regular operators. `in` sometimes
// (when parsing `for`) needs to be tested against specifically, so
// we assign a variable name to it for quick comparing.
var _in = {keyword: "in", binop: 7, beforeExpr: true};
// Map keyword names to token types.
var keywordTypes = {"break": _break, "case": _case, "catch": _catch,
"continue": _continue, "debugger": _debugger, "default": _default,
"do": _do, "else": _else, "finally": _finally, "for": _for,
"function": _function, "if": _if, "return": _return, "switch": _switch,
"throw": _throw, "try": _try, "var": _var, "while": _while, "with": _with,
"null": _null, "true": _true, "false": _false, "new": _new, "in": _in,
"instanceof": {keyword: "instanceof", binop: 7},
"typeof": {keyword: "typeof", prefix: true},
"void": {keyword: "void", prefix: true},
"delete": {keyword: "delete", prefix: true}};
// Punctuation token types. Again, the `type` property is purely for debugging.
var _bracketL = {type: "[", beforeExpr: true}, _bracketR = {type: "]"}, _braceL = {type: "{", beforeExpr: true};
var _braceR = {type: "}"}, _parenL = {type: "(", beforeExpr: true}, _parenR = {type: ")"};
var _comma = {type: ",", beforeExpr: true}, _semi = {type: ";", beforeExpr: true};
var _colon = {type: ":", beforeExpr: true}, _dot = {type: "."}, _question = {type: "?", beforeExpr: true};
// Operators. These carry several kinds of properties to help the
// parser use them properly (the presence of these properties is
// what categorizes them as operators).
//
// `binop`, when present, specifies that this operator is a binary
// operator, and will refer to its precedence.
//
// `prefix` and `postfix` mark the operator as a prefix or postfix
// unary operator. `isUpdate` specifies that the node produced by
// the operator should be of type UpdateExpression rather than
// simply UnaryExpression (`++` and `--`).
//
// `isAssign` marks all of `=`, `+=`, `-=` etcetera, which act as
// binary operators with a very low precedence, that should result
// in AssignmentExpression nodes.
var _slash = {binop: 10, beforeExpr: true}, _eq = {isAssign: true, beforeExpr: true};
var _assign = {isAssign: true, beforeExpr: true}, _plusmin = {binop: 9, prefix: true, beforeExpr: true};
var _incdec = {postfix: true, prefix: true, isUpdate: true}, _prefix = {prefix: true, beforeExpr: true};
var _bin1 = {binop: 1, beforeExpr: true}, _bin2 = {binop: 2, beforeExpr: true};
var _bin3 = {binop: 3, beforeExpr: true}, _bin4 = {binop: 4, beforeExpr: true};
var _bin5 = {binop: 5, beforeExpr: true}, _bin6 = {binop: 6, beforeExpr: true};
var _bin7 = {binop: 7, beforeExpr: true}, _bin8 = {binop: 8, beforeExpr: true};
var _bin10 = {binop: 10, beforeExpr: true};
// This is a trick taken from Esprima. It turns out that, on
// non-Chrome browsers, to check whether a string is in a set, a
// predicate containing a big ugly `switch` statement is faster than
// a regular expression, and on Chrome the two are about on par.
// This function uses `eval` (non-lexical) to produce such a
// predicate from a space-separated string of words.
//
// It starts by sorting the words by length.
function makePredicate(words) {
words = words.split(" ");
var f = "(function(str){", cats = [];
out: for (var i = 0; i < words.length; ++i) {
for (var j = 0; j < cats.length; ++j)
if (cats[j][0].length == words[i].length) {
cats[j].push(words[i]);
continue out;
}
cats.push([words[i]]);
}
function compareTo(arr) {
if (arr.length == 1) return f += "return str === " + JSON.stringify(arr[0]) + ";";
f += "switch(str){";
for (var i = 0; i < arr.length; ++i) f += "case " + JSON.stringify(arr[i]) + ":";
f += "return true}return false;";
}
// When there are more than three length categories, an outer
// switch first dispatches on the lengths, to save on comparisons.
if (cats.length > 3) {
cats.sort(function(a, b) {return b.length - a.length;});
f += "switch(str.length){";
for (var i = 0; i < cats.length; ++i) {
var cat = cats[i];
f += "case " + cat[0].length + ":";
compareTo(cat);
}
f += "}";
// Otherwise, simply generate a flat `switch` statement.
} else {
compareTo(words);
}
return (1, eval)(f + "})");
}
// The ECMAScript 3 reserved word list.
var isReservedWord3 = makePredicate("abstract boolean byte char class double enum export extends final float goto implements import int interface long native package private protected public short static super synchronized throws transient volatile");
// ECMAScript 5 reserved words.
var isReservedWord5 = makePredicate("class enum extends super const export import");
// The additional reserved words in strict mode.
var isStrictReservedWord = makePredicate("implements interface let package private protected public static yield");
// The forbidden variable names in strict mode.
var isStrictBadIdWord = makePredicate("eval arguments");
// And the keywords.
var isKeyword = makePredicate("break case catch continue debugger default do else finally for function if return switch throw try var while with null true false instanceof typeof void delete new in");
// ## Character categories
// Big ugly regular expressions that match characters in the
// whitespace, identifier, and identifier-start categories. These
// are only applied when a character is found to actually have a
// code point above 128.
var nonASCIIwhitespace = /[\u1680\u180E\u2000-\u200A\u202F\u205F\u3000\uFEFF]/;
var nonASCIIidentifierStartChars = "\xaa\xb5\xba\xc0-\xd6\xd8-\xf6\xf8-\u02c1\u02c6-\u02d1\u02e0-\u02e4\u02ec\u02ee\u0370-\u0374\u0376\u0377\u037a-\u037d\u0386\u0388-\u038a\u038c\u038e-\u03a1\u03a3-\u03f5\u03f7-\u0481\u048a-\u0527\u0531-\u0556\u0559\u0561-\u0587\u05d0-\u05ea\u05f0-\u05f2\u0620-\u064a\u066e\u066f\u0671-\u06d3\u06d5\u06e5\u06e6\u06ee\u06ef\u06fa-\u06fc\u06ff\u0710\u0712-\u072f\u074d-\u07a5\u07b1\u07ca-\u07ea\u07f4\u07f5\u07fa\u0800-\u0815\u081a\u0824\u0828\u0840-\u0858\u08a0\u08a2-\u08ac\u0904-\u0939\u093d\u0950\u0958-\u0961\u0971-\u0977\u0979-\u097f\u0985-\u098c\u098f\u0990\u0993-\u09a8\u09aa-\u09b0\u09b2\u09b6-\u09b9\u09bd\u09ce\u09dc\u09dd\u09df-\u09e1\u09f0\u09f1\u0a05-\u0a0a\u0a0f\u0a10\u0a13-\u0a28\u0a2a-\u0a30\u0a32\u0a33\u0a35\u0a36\u0a38\u0a39\u0a59-\u0a5c\u0a5e\u0a72-\u0a74\u0a85-\u0a8d\u0a8f-\u0a91\u0a93-\u0aa8\u0aaa-\u0ab0\u0ab2\u0ab3\u0ab5-\u0ab9\u0abd\u0ad0\u0ae0\u0ae1\u0b05-\u0b0c\u0b0f\u0b10\u0b13-\u0b28\u0b2a-\u0b30\u0b32\u0b33\u0b35-\u0b39\u0b3d\u0b5c\u0b5d\u0b5f-\u0b61\u0b71\u0b83\u0b85-\u0b8a\u0b8e-\u0b90\u0b92-\u0b95\u0b99\u0b9a\u0b9c\u0b9e\u0b9f\u0ba3\u0ba4\u0ba8-\u0baa\u0bae-\u0bb9\u0bd0\u0c05-\u0c0c\u0c0e-\u0c10\u0c12-\u0c28\u0c2a-\u0c33\u0c35-\u0c39\u0c3d\u0c58\u0c59\u0c60\u0c61\u0c85-\u0c8c\u0c8e-\u0c90\u0c92-\u0ca8\u0caa-\u0cb3\u0cb5-\u0cb9\u0cbd\u0cde\u0ce0\u0ce1\u0cf1\u0cf2\u0d05-\u0d0c\u0d0e-\u0d10\u0d12-\u0d3a\u0d3d\u0d4e\u0d60\u0d61\u0d7a-\u0d7f\u0d85-\u0d96\u0d9a-\u0db1\u0db3-\u0dbb\u0dbd\u0dc0-\u0dc6\u0e01-\u0e30\u0e32\u0e33\u0e40-\u0e46\u0e81\u0e82\u0e84\u0e87\u0e88\u0e8a\u0e8d\u0e94-\u0e97\u0e99-\u0e9f\u0ea1-\u0ea3\u0ea5\u0ea7\u0eaa\u0eab\u0ead-\u0eb0\u0eb2\u0eb3\u0ebd\u0ec0-\u0ec4\u0ec6\u0edc-\u0edf\u0f00\u0f40-\u0f47\u0f49-\u0f6c\u0f88-\u0f8c\u1000-\u102a\u103f\u1050-\u1055\u105a-\u105d\u1061\u1065\u1066\u106e-\u1070\u1075-\u1081\u108e\u10a0-\u10c5\u10c7\u10cd\u10d0-\u10fa\u10fc-\u1248\u124a-\u124d\u1250-\u1256\u1258\u125a-\u125d\u1260-\u1288\u128a-\u128d\u1290-\u12b0\u12b2-\u12b5\u12b8-\u12be\u12c0\u12c2-\u12c5\u12c8-\u12d6\u12d8-\u1310\u1312-\u1315\u1318-\u135a\u1380-\u138f\u13a0-\u13f4\u1401-\u166c\u166f-\u167f\u1681-\u169a\u16a0-\u16ea\u16ee-\u16f0\u1700-\u170c\u170e-\u1711\u1720-\u1731\u1740-\u1751\u1760-\u176c\u176e-\u1770\u1780-\u17b3\u17d7\u17dc\u1820-\u1877\u1880-\u18a8\u18aa\u18b0-\u18f5\u1900-\u191c\u1950-\u196d\u1970-\u1974\u1980-\u19ab\u19c1-\u19c7\u1a00-\u1a16\u1a20-\u1a54\u1aa7\u1b05-\u1b33\u1b45-\u1b4b\u1b83-\u1ba0\u1bae\u1baf\u1bba-\u1be5\u1c00-\u1c23\u1c4d-\u1c4f\u1c5a-\u1c7d\u1ce9-\u1cec\u1cee-\u1cf1\u1cf5\u1cf6\u1d00-\u1dbf\u1e00-\u1f15\u1f18-\u1f1d\u1f20-\u1f45\u1f48-\u1f4d\u1f50-\u1f57\u1f59\u1f5b\u1f5d\u1f5f-\u1f7d\u1f80-\u1fb4\u1fb6-\u1fbc\u1fbe\u1fc2-\u1fc4\u1fc6-\u1fcc\u1fd0-\u1fd3\u1fd6-\u1fdb\u1fe0-\u1fec\u1ff2-\u1ff4\u1ff6-\u1ffc\u2071\u207f\u2090-\u209c\u2102\u2107\u210a-\u2113\u2115\u2119-\u211d\u2124\u2126\u2128\u212a-\u212d\u212f-\u2139\u213c-\u213f\u2145-\u2149\u214e\u2160-\u2188\u2c00-\u2c2e\u2c30-\u2c5e\u2c60-\u2ce4\u2ceb-\u2cee\u2cf2\u2cf3\u2d00-\u2d25\u2d27\u2d2d\u2d30-\u2d67\u2d6f\u2d80-\u2d96\u2da0-\u2da6\u2da8-\u2dae\u2db0-\u2db6\u2db8-\u2dbe\u2dc0-\u2dc6\u2dc8-\u2dce\u2dd0-\u2dd6\u2dd8-\u2dde\u2e2f\u3005-\u3007\u3021-\u3029\u3031-\u3035\u3038-\u303c\u3041-\u3096\u309d-\u309f\u30a1-\u30fa\u30fc-\u30ff\u3105-\u312d\u3131-\u318e\u31a0-\u31ba\u31f0-\u31ff\u3400-\u4db5\u4e00-\u9fcc\ua000-\ua48c\ua4d0-\ua4fd\ua500-\ua60c\ua610-\ua61f\ua62a\ua62b\ua640-\ua66e\ua67f-\ua697\ua6a0-\ua6ef\ua717-\ua71f\ua722-\ua788\ua78b-\ua78e\ua790-\ua793\ua7a0-\ua7aa\ua7f8-\ua801\ua803-\ua805\ua807-\ua80a\ua80c-\ua822\ua840-\ua873\ua882-\ua8b3\ua8f2-\ua8f7\ua8fb\ua90a-\ua925\ua930-\ua946\ua960-\ua97c\ua984-\ua9b2\ua9cf\uaa00-\uaa28\uaa40-\uaa42\uaa44-\uaa4b\uaa60-\uaa76\uaa7a\uaa80-\uaaaf\uaab1\uaab5\uaab6\uaab9-\uaabd\uaac0\uaac2\uaadb-\uaadd\uaae0-\uaaea\uaaf2-\uaaf4\uab01-\uab06\uab09-\uab0e\uab11-\uab16\uab20-\uab26\uab28-\uab2e\uabc0-\uabe2\uac00-\ud7a3\ud7b0-\ud7c6\ud7cb-\ud7fb\uf900-\ufa6d\ufa70-\ufad9\ufb00-\ufb06\ufb13-\ufb17\ufb1d\ufb1f-\ufb28\ufb2a-\ufb36\ufb38-\ufb3c\ufb3e\ufb40\ufb41\ufb43\ufb44\ufb46-\ufbb1\ufbd3-\ufd3d\ufd50-\ufd8f\ufd92-\ufdc7\ufdf0-\ufdfb\ufe70-\ufe74\ufe76-\ufefc\uff21-\uff3a\uff41-\uff5a\uff66-\uffbe\uffc2-\uffc7\uffca-\uffcf\uffd2-\uffd7\uffda-\uffdc";
var nonASCIIidentifierChars = "\u0371-\u0374\u0483-\u0487\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u0620-\u0649\u0672-\u06d3\u06e7-\u06e8\u06fb-\u06fc\u0730-\u074a\u0800-\u0814\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0840-\u0857\u08e4-\u08fe\u0900-\u0903\u093a-\u093c\u093e-\u094f\u0951-\u0957\u0962-\u0963\u0966-\u096f\u0981-\u0983\u09bc\u09be-\u09c4\u09c7\u09c8\u09d7\u09df-\u09e0\u0a01-\u0a03\u0a3c\u0a3e-\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a66-\u0a71\u0a75\u0a81-\u0a83\u0abc\u0abe-\u0ac5\u0ac7-\u0ac9\u0acb-\u0acd\u0ae2-\u0ae3\u0ae6-\u0aef\u0b01-\u0b03\u0b3c\u0b3e-\u0b44\u0b47\u0b48\u0b4b-\u0b4d\u0b56\u0b57\u0b5f-\u0b60\u0b66-\u0b6f\u0b82\u0bbe-\u0bc2\u0bc6-\u0bc8\u0bca-\u0bcd\u0bd7\u0be6-\u0bef\u0c01-\u0c03\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62-\u0c63\u0c66-\u0c6f\u0c82\u0c83\u0cbc\u0cbe-\u0cc4\u0cc6-\u0cc8\u0cca-\u0ccd\u0cd5\u0cd6\u0ce2-\u0ce3\u0ce6-\u0cef\u0d02\u0d03\u0d46-\u0d48\u0d57\u0d62-\u0d63\u0d66-\u0d6f\u0d82\u0d83\u0dca\u0dcf-\u0dd4\u0dd6\u0dd8-\u0ddf\u0df2\u0df3\u0e34-\u0e3a\u0e40-\u0e45\u0e50-\u0e59\u0eb4-\u0eb9\u0ec8-\u0ecd\u0ed0-\u0ed9\u0f18\u0f19\u0f20-\u0f29\u0f35\u0f37\u0f39\u0f41-\u0f47\u0f71-\u0f84\u0f86-\u0f87\u0f8d-\u0f97\u0f99-\u0fbc\u0fc6\u1000-\u1029\u1040-\u1049\u1067-\u106d\u1071-\u1074\u1082-\u108d\u108f-\u109d\u135d-\u135f\u170e-\u1710\u1720-\u1730\u1740-\u1750\u1772\u1773\u1780-\u17b2\u17dd\u17e0-\u17e9\u180b-\u180d\u1810-\u1819\u1920-\u192b\u1930-\u193b\u1951-\u196d\u19b0-\u19c0\u19c8-\u19c9\u19d0-\u19d9\u1a00-\u1a15\u1a20-\u1a53\u1a60-\u1a7c\u1a7f-\u1a89\u1a90-\u1a99\u1b46-\u1b4b\u1b50-\u1b59\u1b6b-\u1b73\u1bb0-\u1bb9\u1be6-\u1bf3\u1c00-\u1c22\u1c40-\u1c49\u1c5b-\u1c7d\u1cd0-\u1cd2\u1d00-\u1dbe\u1e01-\u1f15\u200c\u200d\u203f\u2040\u2054\u20d0-\u20dc\u20e1\u20e5-\u20f0\u2d81-\u2d96\u2de0-\u2dff\u3021-\u3028\u3099\u309a\ua640-\ua66d\ua674-\ua67d\ua69f\ua6f0-\ua6f1\ua7f8-\ua800\ua806\ua80b\ua823-\ua827\ua880-\ua881\ua8b4-\ua8c4\ua8d0-\ua8d9\ua8f3-\ua8f7\ua900-\ua909\ua926-\ua92d\ua930-\ua945\ua980-\ua983\ua9b3-\ua9c0\uaa00-\uaa27\uaa40-\uaa41\uaa4c-\uaa4d\uaa50-\uaa59\uaa7b\uaae0-\uaae9\uaaf2-\uaaf3\uabc0-\uabe1\uabec\uabed\uabf0-\uabf9\ufb20-\ufb28\ufe00-\ufe0f\ufe20-\ufe26\ufe33\ufe34\ufe4d-\ufe4f\uff10-\uff19\uff3f";
var nonASCIIidentifierStart = new RegExp("[" + nonASCIIidentifierStartChars + "]");
var nonASCIIidentifier = new RegExp("[" + nonASCIIidentifierStartChars + nonASCIIidentifierChars + "]");
// Whether a single character denotes a newline.
var newline = /[\n\r\u2028\u2029]/;
// Matches a whole line break (where CRLF is considered a single
// line break). Used to count lines.
var lineBreak = /\r\n?|[\n\r\u2028\u2029]/g;
// Test whether a given character code starts an identifier.
function isIdentifierStart(code) {
return (code >= 65 && code <= 90) || (code >= 97 && code <= 122) ||
code === 36 || code === 95 ||
(code >= 0xaa && nonASCIIidentifierStart.test(String.fromCharCode(code)));
}
// Test whether a given character is part of an identifier.
function isIdentifierChar(ch) {
return ((ch >= "a" && ch <= "z") || (ch >= "A" && ch <= "Z") ||
(ch >= "0" && ch <= "9") || ch === "$" || ch === "_" ||
(ch >= "\xaa" && nonASCIIidentifier.test(ch)));
}
// ## Tokenizer
// These are used when `options.locations` is on, in order to track
// the current line number and start of line offset, in order to set
// `tokStartLoc` and `tokEndLoc`.
function nextLineStart() {
lineBreak.lastIndex = tokLineStart;
var match = lineBreak.exec(input);
return match ? match.index + match[0].length : input.length + 1;
}
function curLineLoc() {
while (tokLineStartNext <= tokPos) {
++tokCurLine;
tokLineStart = tokLineStartNext;
tokLineStartNext = nextLineStart();
}
return {line: tokCurLine, column: tokPos - tokLineStart};
}
// Reset the token state. Used at the start of a parse.
function initTokenState() {
tokCurLine = 1;
tokPos = tokLineStart = 0;
tokLineStartNext = nextLineStart();
tokRegexpAllowed = true;
tokComments = null;
skipSpace();
}
// Called at the end of every token. Sets `tokEnd`, `tokVal`,
// `tokCommentsAfter`, and `tokRegexpAllowed`, and skips the space
// after the token, so that the next one's `tokStart` will point at
// the right position.
function finishToken(type, val) {
tokEnd = tokPos;
if (options.locations) tokEndLoc = curLineLoc();
tokType = type;
skipSpace();
tokVal = val;
tokCommentsAfter = tokComments;
tokRegexpAllowed = type.beforeExpr;
}
function skipBlockComment() {
var end = input.indexOf("*/", tokPos += 2);
if (end === -1) raise(tokPos - 2, "Unterminated comment");
if (options.trackComments)
(tokComments || (tokComments = [])).push(input.slice(tokPos, end));
tokPos = end + 2;
}
function skipLineComment() {
var start = tokPos;
tokPos += 2;
while (tokPos < inputLen && !newline.test(input.charAt(tokPos))) ++tokPos;
if (options.trackComments)
(tokComments || (tokComments = [])).push(input.slice(start, tokPos));
}
// Called at the start of the parse and after every token. Skips
// whitespace and comments, and, if `options.trackComments` is on,
// will store all skipped comments in `tokComments`.
function skipSpace() {
tokComments = null;
while (tokPos < inputLen) {
var ch = input.charAt(tokPos);
if (ch === "/") {
var nextCh = input.charAt(tokPos+1);
if (nextCh === "*") {
skipBlockComment();
} else if (nextCh === "/") {
skipLineComment();
} else break;
} else if (ch === " " || ch === '\t' || ch === "\n" || ch === "\r" || ch === "\f" ||
ch === "\xa0" || ch === "\x0b" || (ch >= "\u1680" && nonASCIIwhitespace.test(ch))) {
++tokPos;
} else {
break;
}
}
}
// ### Token reading
// This is the function that is called to fetch the next token. It
// is somewhat obscure, because it works in character codes rather
// than characters, and because operator parsing has been inlined
// into it.
//
// All in the name of speed.
//
// The `forceRegexp` parameter is used in the one case where the
// `tokRegexpAllowed` trick does not work. See `parseStatement`.
function readToken(forceRegexp) {
tokStart = tokPos;
if (options.locations) tokStartLoc = curLineLoc();
tokCommentsBefore = tokComments;
if (forceRegexp) return readRegexp();
if (tokPos >= inputLen) return finishToken(_eof);
var code = input.charCodeAt(tokPos);
// Identifier or keyword. '\uXXXX' sequences are allowed in
// identifiers, so '\' also dispatches to that.
if (isIdentifierStart(code) || code === 92 /* '\' */) return readWord();
var next = input.charCodeAt(tokPos+1);
switch(code) {
// The interpretation of a dot depends on whether it is followed
// by a digit.
case 46: // '.'
if (next >= 48 && next <= 57) return readNumber(String.fromCharCode(code));
++tokPos;
return finishToken(_dot);
// Punctuation tokens.
case 40: ++tokPos; return finishToken(_parenL);
case 41: ++tokPos; return finishToken(_parenR);
case 59: ++tokPos; return finishToken(_semi);
case 44: ++tokPos; return finishToken(_comma);
case 91: ++tokPos; return finishToken(_bracketL);
case 93: ++tokPos; return finishToken(_bracketR);
case 123: ++tokPos; return finishToken(_braceL);
case 125: ++tokPos; return finishToken(_braceR);
case 58: ++tokPos; return finishToken(_colon);
case 63: ++tokPos; return finishToken(_question);
// '0x' is a hexadecimal number.
case 48: // '0'
if (next === 120 || next === 88) return readHexNumber();
// Anything else beginning with a digit is an integer, octal
// number, or float.
case 49: case 50: case 51: case 52: case 53: case 54: case 55: case 56: case 57: // 1-9
return readNumber(String.fromCharCode(code));
// Quotes produce strings.
case 34: case 39: // '"', "'"
return readString(String.fromCharCode(code));
// Operators are parsed inline in tiny state machines. '=' (61) is
// often referred to. `finishOp` simply skips the amount of
// characters it is given as second argument, and returns a token
// of the type given by its first argument.
case 47: // '/'
if (tokRegexpAllowed) {++tokPos; return readRegexp();}
if (next === 61) return finishOp(_assign, 2);
return finishOp(_slash, 1);
case 37: case 42: // '%*'
if (next === 61) return finishOp(_assign, 2);
return finishOp(_bin10, 1);
case 124: case 38: // '|&'
if (next === code) return finishOp(code === 124 ? _bin1 : _bin2, 2);
if (next === 61) return finishOp(_assign, 2);
return finishOp(code === 124 ? _bin3 : _bin5, 1);
case 94: // '^'
if (next === 61) return finishOp(_assign, 2);
return finishOp(_bin4, 1);
case 43: case 45: // '+-'
if (next === code) return finishOp(_incdec, 2);
if (next === 61) return finishOp(_assign, 2);
return finishOp(_plusmin, 1);
case 60: case 62: // '<>'
var size = 1;
if (next === code) {
size = code === 62 && input.charCodeAt(tokPos+2) === 62 ? 3 : 2;
if (input.charCodeAt(tokPos + size) === 61) return finishOp(_assign, size + 1);
return finishOp(_bin8, size);
}
if (next === 61)
size = input.charCodeAt(tokPos+2) === 61 ? 3 : 2;
return finishOp(_bin7, size);
case 61: case 33: // '=!'
if (next === 61) return finishOp(_bin6, input.charCodeAt(tokPos+2) === 61 ? 3 : 2);
return finishOp(code === 61 ? _eq : _prefix, 1);
case 126: // '~'
if (next === 61) return finishOp(_assign, 2);
return finishOp(_prefix, 1);
}
// If we are here, we either found a non-ASCII identifier
// character, or something that's entirely disallowed.
var ch = String.fromCharCode(code);
if (ch === "\\" || nonASCIIidentifierStart.test(ch)) return readWord();
raise(tokPos, "Unexpected character '" + ch + "'");
}
function finishOp(type, size) {
var str = input.slice(tokPos, tokPos + size);
tokPos += size;
finishToken(type, str);
}
// Parse a regular expression. Some context-awareness is necessary,
// since a '/' inside a '[]' set does not end the expression.
function readRegexp() {
var content = "", escaped, inClass, start = tokPos;
for (;;) {
if (tokPos >= inputLen) raise(start, "Unterminated regular expression");
var ch = input.charAt(tokPos);
if (newline.test(ch)) raise(start, "Unterminated regular expression");
if (!escaped) {
if (ch === "[") inClass = true;
else if (ch === "]" && inClass) inClass = false;
else if (ch === "/" && !inClass) break;
escaped = ch === "\\";
} else escaped = false;
++tokPos;
}
var content = input.slice(start, tokPos);
++tokPos;
// Need to use `readWord1` because '\uXXXX' sequences are allowed
// here (don't ask).
var mods = readWord1();
if (mods && !/^[gmsiy]*$/.test(mods)) raise(start, "Invalid regexp flag");
return finishToken(_regexp, new RegExp(content, mods));
}
// Read an integer in the given radix. Return null if zero digits
// were read, the integer value otherwise. When `len` is given, this
// will return `null` unless the integer has exactly `len` digits.
function readInt(radix, len) {
var start = tokPos, total = 0;
for (;;) {
var code = input.charCodeAt(tokPos), val;
if (code >= 97) val = code - 97 + 10; // a
else if (code >= 65) val = code - 65 + 10; // A
else if (code >= 48 && code <= 57) val = code - 48; // 0-9
else val = Infinity;
if (val >= radix) break;
++tokPos;
total = total * radix + val;
}
if (tokPos === start || len != null && tokPos - start !== len) return null;
return total;
}
function readHexNumber() {
tokPos += 2; // 0x
var val = readInt(16);
if (val == null) raise(tokStart + 2, "Expected hexadecimal number");
if (isIdentifierStart(input.charCodeAt(tokPos))) raise(tokPos, "Identifier directly after number");
return finishToken(_num, val);
}
// Read an integer, octal integer, or floating-point number.
function readNumber(ch) {
var start = tokPos, isFloat = ch === ".";
if (!isFloat && readInt(10) == null) raise(start, "Invalid number");
if (isFloat || input.charAt(tokPos) === ".") {
var next = input.charAt(++tokPos);
if (next === "-" || next === "+") ++tokPos;
if (readInt(10) === null) raise(start, "Invalid number");
isFloat = true;
}
if (/e/i.test(input.charAt(tokPos))) {
var next = input.charAt(++tokPos);
if (next === "-" || next === "+") ++tokPos;
if (readInt(10) === null) raise(start, "Invalid number")
isFloat = true;
}
if (isIdentifierStart(input.charCodeAt(tokPos))) raise(tokPos, "Identifier directly after number");
var str = input.slice(start, tokPos), val;
if (isFloat) val = parseFloat(str);
else if (ch !== "0" || str.length === 1) val = parseInt(str, 10);
else if (/[89]/.test(str) || strict) raise(start, "Invalid number");
else val = parseInt(str, 8);
return finishToken(_num, val);
}
// Read a string value, interpreting backslash-escapes.
function readString(quote) {
tokPos++;
var str = "";
for (;;) {
if (tokPos >= inputLen) raise(tokStart, "Unterminated string constant");
var ch = input.charAt(tokPos);
if (ch === quote) {
++tokPos;
return finishToken(_string, str);
}
if (ch === "\\") {
ch = input.charAt(++tokPos);
var octal = /^[0-7]+/.exec(input.slice(tokPos, tokPos + 3));
if (octal) octal = octal[0];
while (octal && parseInt(octal, 8) > 255) octal = octal.slice(0, octal.length - 1);
++tokPos;
if (octal) {
if (strict) raise(tokPos - 2, "Octal literal in strict mode");
str += String.fromCharCode(parseInt(octal, 8));
tokPos += octal.length - 1;
} else if (ch === "x") {
str += readHexChar(2);
} else if (ch === "u") {
str += readHexChar(4);
} else if (ch === "U") {
str += readHexChar(8);
} else {
switch (ch) {
case "n" : str += "\n"; break;
case "r" : str += "\r"; break;
case "t" : str += "\t"; break;
case "b" : str += "\b"; break;
case "v" : str += "\u000b"; break;
case "f" : str += "\f"; break;
case "0" : str += "\0"; break;
case "\r": if (input.charAt(tokPos) === "\n") ++tokPos;
case "\n": break;
default: str += ch; break;
}
}
} else {
if (newline.test(ch)) raise(tokStart, "Unterminated string constant");
if (ch !== "\\") str += ch;
++tokPos;
}
}
}
// Used to read character escape sequences ('\x', '\u', '\U').
function readHexChar(len) {
var n = readInt(16, len);
if (n === null) raise(tokStart, "Bad character escape sequence");
return String.fromCharCode(n);
}
// Used to signal to callers of `readWord1` whether the word
// contained any escape sequences. This is needed because words with
// escape sequences must not be interpreted as keywords.
var containsEsc;
// Read an identifier, and return it as a string. Sets `containsEsc`
// to whether the word contained a '\u' escape.
//
// Only builds up the word character-by-character when it actually
// containeds an escape, as a micro-optimization.
function readWord1() {
containsEsc = false;
var word, first = true, start = tokPos;
for (;;) {
var ch = input.charAt(tokPos);
if (isIdentifierChar(ch)) {
if (containsEsc) word += ch;
++tokPos;
} else if (ch === "\\") {
if (!containsEsc) word = input.slice(start, tokPos);
containsEsc = true;
if (input.charAt(++tokPos) != "u")
raise(tokPos, "Expecting Unicode escape sequence \\uXXXX");
++tokPos;
var esc = readHexChar(4);
if (!esc) raise(tokPos - 1, "Invalid Unicode escape");
if (!(first ? isIdentifierStart(esc.charCodeAt(0)) : isIdentifierChar(esc)))
raise(tokPos - 4, "Invalid Unicode escape");
word += esc;
} else {
break;
}
first = false;
}
return containsEsc ? word : input.slice(start, tokPos);
}
// Read an identifier or keyword token. Will check for reserved
// words when necessary.
function readWord() {
var word = readWord1();
var type = _name;
if (!containsEsc) {
if (isKeyword(word)) type = keywordTypes[word];
else if (options.forbidReserved &&
(options.ecmaVersion === 3 ? isReservedWord3 : isReservedWord5)(word) ||
strict && isStrictReservedWord(word))
raise(tokStart, "The keyword '" + word + "' is reserved");
}
return finishToken(type, word);
}
// ## Parser
// A recursive descent parser operates by defining functions for all
// syntactic elements, and recursively calling those, each function
// advancing the input stream and returning an AST node. Precedence
// of constructs (for example, the fact that `!x[1]` means `!(x[1])`
// instead of `(!x)[1]` is handled by the fact that the parser
// function that parses unary prefix operators is called first, and
// in turn calls the function that parses `[]` subscripts — that
// way, it'll receive the node for `x[1]` already parsed, and wraps
// *that* in the unary operator node.
//
// Acorn uses an [operator precedence parser][opp] to handle binary
// operator precedence, because it is much more compact than using
// the technique outlined above, which uses different, nesting
// functions to specify precedence, for all of the ten binary
// precedence levels that JavaScript defines.
//
// [opp]: http://en.wikipedia.org/wiki/Operator-precedence_parser
// ### Parser utilities
// Continue to the next token.
function next() {
lastStart = tokStart;
lastEnd = tokEnd;
lastEndLoc = tokEndLoc;
readToken();
}
// Enter strict mode. Re-reads the next token to please pedantic
// tests ("use strict"; 010; -- should fail).
function setStrict(strct) {
strict = strct;
tokPos = lastEnd;
skipSpace();
readToken();
}
// Start an AST node, attaching a start offset and optionally a
// `commentsBefore` property to it.
function startNode() {
var node = {type: null, start: tokStart, end: null};
if (options.trackComments && tokCommentsBefore) {
node.commentsBefore = tokCommentsBefore;
tokCommentsBefore = null;
}
if (options.locations)
node.loc = {start: tokStartLoc, end: null};
return node;
}
// Start a node whose start offset/comments information should be
// based on the start of another node. For example, a binary
// operator node is only started after its left-hand side has
// already been parsed.
function startNodeFrom(other) {
var node = {type: null, start: other.start};
if (other.commentsBefore) {
node.commentsBefore = other.commentsBefore;
other.commentsBefore = null;
}
if (options.locations)
node.loc = {start: other.loc.start, end: null};
return node;
}
// Finish an AST node, adding `type`, `end`, and `commentsAfter`
// properties.
//
// We keep track of the last node that we finished, in order
// 'bubble' `commentsAfter` properties up to the biggest node. I.e.
// in '`1 + 1 // foo', the comment should be attached to the binary
// operator node, not the second literal node.
var lastFinishedNode;
function finishNode(node, type) {
node.type = type;
node.end = lastEnd;
if (options.trackComments) {
if (tokCommentsAfter) {
node.commentsAfter = tokCommentsAfter;
tokCommentsAfter = null;
} else if (lastFinishedNode && lastFinishedNode.end === lastEnd) {
node.commentsAfter = lastFinishedNode.commentsAfter;
lastFinishedNode.commentsAfter = null;
}
lastFinishedNode = node;
}
if (options.locations)
node.loc.end = lastEndLoc;
return node;
}
// Test whether a statement node is the string literal `"use strict"`.
function isUseStrict(stmt) {
return options.ecmaVersion >= 5 && stmt.type === "ExpressionStatement" &&
stmt.expression.type === "Literal" && stmt.expression.value === "use strict";
}
// Predicate that tests whether the next token is of the given
// type, and if yes, consumes it as a side effect.
function eat(type) {
if (tokType === type) {
next();
return true;
}
}
// Test whether a semicolon can be inserted at the current position.
function canInsertSemicolon() {
return tokType === _eof || tokType === _braceR ||
!options.strictSemicolons &&
newline.test(input.slice(lastEnd, tokStart));
}
// Consume a semicolon, or, failing that, see if we are allowed to
// pretend that there is a semicolon at this position.
function semicolon() {
if (!eat(_semi) && !canInsertSemicolon()) unexpected();
}
// Expect a token of a given type. If found, consume it, otherwise,
// raise an unexpected token error.
function expect(type) {
if (tokType === type) next();
else unexpected();
}
// Raise an unexpected token error.
function unexpected() {
raise(tokStart, "Unexpected token");
}
// Verify that a node is an lval — something that can be assigned
// to.
function checkLVal(expr) {
if (expr.type !== "Identifier" && expr.type !== "MemberExpression")
raise(expr.start, "Assigning to rvalue");
if (strict && expr.type === "Identifier" && isStrictBadIdWord(expr.name))
raise(expr.start, "Assigning to " + expr.name + " in strict mode");
}
// ### Statement parsing
// Parse a program. Initializes the parser, reads any number of
// statements, and wraps them in a Program node.
function parseTopLevel() {
initTokenState();
lastStart = lastEnd = tokPos;
if (options.locations) lastEndLoc = curLineLoc();
inFunction = strict = null;
labels = [];
readToken();
var node = startNode(), first = true;
node.body = [];
while (tokType !== _eof) {
var stmt = parseStatement();
node.body.push(stmt);
if (first && isUseStrict(stmt)) setStrict(true);
first = false;
}
return finishNode(node, "Program");
};
var loopLabel = {kind: "loop"}, switchLabel = {kind: "switch"};
// Parse a single statement.
//
// If expecting a statement and finding a slash operator, parse a
// regular expression literal. This is to handle cases like
// `if (foo) /blah/.exec(foo);`, where looking at the previous token
// does not help.
function parseStatement() {
if (tokType === _slash)
readToken(true);
var starttype = tokType, node = startNode();
// Most types of statements are recognized by the keyword they
// start with. Many are trivial to parse, some require a bit of
// complexity.
switch (starttype) {
case _break: case _continue:
next();
var isBreak = starttype === _break;
if (eat(_semi) || canInsertSemicolon()) node.label = null;
else if (tokType !== _name) unexpected();
else {
node.label = parseIdent();
semicolon();
}
// Verify that there is an actual destination to break or
// continue to.
for (var i = 0; i < labels.length; ++i) {
var lab = labels[i];
if (node.label == null || lab.name === node.label.name) {
if (lab.kind != null && (isBreak || lab.kind === "loop")) break;
if (node.label && isBreak) break;
}
}
if (i === labels.length) raise(node.start, "Unsyntactic " + starttype.keyword);
return finishNode(node, isBreak ? "BreakStatement" : "ContinueStatement");
case _debugger:
next();
return finishNode(node, "DebuggerStatement");
case _do:
next();
labels.push(loopLabel);
node.body = parseStatement();
labels.pop();
expect(_while);
node.test = parseParenExpression();
return finishNode(node, "DoWhileStatement");
// Disambiguating between a `for` and a `for`/`in` loop is
// non-trivial. Basically, we have to parse the init `var`
// statement or expression, disallowing the `in` operator (see
// the second parameter to `parseExpression`), and then check
// whether the next token is `in`. When there is no init part
// (semicolon immediately after the opening parenthesis), it is
// a regular `for` loop.