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matcher.js
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matcher.js
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/**
* Defines the internal [[Match]] procedure for |RegExp| objects.
*
* Note: could create a set of match tests with pre-cooked parse trees, but the
* integration tests seem to be doing just fine for now.
*/
var cdlre = (function(cdlre) {
var extend = cdlre.extend,
identity = cdlre.identity,
stringRange = cdlre.stringRange,
isString = cdlre.isString,
ord = cdlre.ord,
chr = cdlre.chr,
Assertion = cdlre.parser.Assertion,
ClassRanges = cdlre.parser.ClassRanges,
Set = cdlre.Set,
assert = cdlre.assert;
// Matcher(State, Continuation) -> MatchResult
// type MatchResult = State | FAILURE
var MatchResult = {FAILURE: "failure"};
var LINE_TERMINATOR = new Set(['\n', '\r', '\u2028', '\u2029']);
function IdentityContinuation(state) { return state; }
function ProcedureBuilder(ast, multiline, ignoreCase, input, index) {
assert(ast !== undefined);
this.ast = ast;
this.multiline = multiline;
this.ignoreCase = ignoreCase;
this.input = input;
this.inputLength = input.length;
this.index = index;
this.nCapturingParens = ast.nCapturingParens;
assert(this.nCapturingParens !== undefined);
this.clog = new Logger('ProcedureBuilder@CompileTime');
this.rlog = new Logger('ProcedureBuilder@RunTime');
this.spec = new Logger('ProcedureBuilder@Spec');
}
/**********************************
* AST-to-continuation transforms *
**********************************/
ProcedureBuilder.prototype.evalPattern = function() {
this.clog.debug("evaluating pattern");
var m = this.evalDisjunction(this.ast.disjunction);
var c = IdentityContinuation;
/* State captures use 1-based indexing. */
var cap = [];
for (var i = 0; i <= this.nCapturingParens; ++i)
cap[i] = undefined;
this.checkCaptures(cap);
var x = this.State(this.index, cap);
return m(x, c);
};
ProcedureBuilder.prototype.evalDisjunction = function(dis) {
this.clog.debug("evaluating disjunction");
if (!dis.disjunction)
return this.evalAlternative(dis.alternative);
var m1 = this.evalAlternative(dis.alternative);
var m2 = this.evalDisjunction(dis.disjunction);
return function matcher(x, c) {
var r = m1(x, c);
if (r !== MatchResult.FAILURE)
return r;
return m2(x, c);
};
};
ProcedureBuilder.prototype.evalAlternative = function(alt) {
this.clog.debug("evaluating alternative");
if (alt.empty)
return function matcher(x, c) { return c(x); };
/*
* Note, right recursive, unlike the ECMA grammar,
* so the alternative matcher is the continuation
* for the term matcher. */
var m1 = this.evalTerm(alt.term);
var m2 = this.evalAlternative(alt.alternative);
return function matcher(x, c) {
var d = function(y) { return m2(y, c); };
return m1(x, d);
};
};
ProcedureBuilder.prototype.evalQuantifier = function(quant) {
/* Now I see why JS needs a lambda syntax... */
var prefix = quant.prefix;
var quantFun = {
Star: function() { return {min: 0, max: Infinity}; },
Plus: function() { return {min: 1, max: Infinity}; },
Question: function() { return {min: 0, max: 1}; },
Fixed: function() { return {min: prefix.value, max: prefix.value}; },
LowerBound: function() { return {min: prefix.value, max: Infinity}; },
Range: function() {
if (prefix.value.length !== 2)
throw new Error("Bad range prefix value: " + prefix.value);
return {min: prefix.value[0], max: prefix.value[1]};
},
}[prefix.kind];
if (!quantFun)
throw new Error("Bad value for quant prefix kind: " + prefix.kind);
var result = quantFun();
result.greedy = !quant.lazy;
result.toString = function() {
var accum = ['{'];
for (var key in result) {
if (!result.hasOwnProperty(key) || key === 'toString')
continue;
accum.push(key, ': ', uneval(result[key]), ', ');
}
accum.pop();
accum.push('}');
return accum.join('');
}
this.clog.debug("Quantifier " + uneval(prefix.kind) + "; result: " + result);
return result;
};
ProcedureBuilder.prototype.evalAssertion = function(assertion) {
var self = this;
if (assertion === Assertion.BOL) {
return function assertionTester(x) {
var e = x.endIndex;
if (e === 0)
return true;
if (!self.multiline)
return false;
return LINE_TERMINATOR.has(self.input[e - 1]);
};
} else if (assertion === Assertion.EOL) {
return function assertionTester(x) {
var e = x.endIndex;
if (e === self.inputLength)
return true;
if (!self.multiline)
return false;
return LINE_TERMINATOR.has(self.input[e]);
};
} else if (assertion.kind === 'ZeroWidthPositive') {
var m = self.evalDisjunction(assertion.disjunction);
return function assertionTester(x, c) {
function d(x) { return x; }
var r = m(x, d);
if (r === MatchResult.FAILURE)
return r;
var y = r;
var cap = y.captures;
var xe = x.endIndex;
var z = self.State(xe, cap);
return c(z);
};
} else if (assertion === Assertion.WB) {
return function assertionTester(x) {
var e = x.endIndex;
var a = self.isWordChar(e - 1);
var b = self.isWordChar(e);
return Boolean(a ^ b);
};
} else {
throw new Error("NYI: " + assertion);
}
};
ProcedureBuilder.prototype.evalTerm = function(term) {
var self = this;
self.clog.debug("evaluating term");
if (term.atom && !term.quantifier && !term.assertion)
return self.evalAtom(term.atom);
if (term.atom && term.quantifier) {
var m = self.evalAtom(term.atom);
var bounds = self.evalQuantifier(term.quantifier);
var min = bounds.min, max = bounds.max, greedy = bounds.greedy;
var parenIndex = term.parenIndex;
var parenCount = term.parenCount;
assert(parenIndex !== undefined, new String(parenIndex));
assert(parenCount !== undefined, new String(parenCount));
return function matcher(x, c) {
return self.repeatMatcher(m, min, max, greedy, x, c, parenIndex, parenCount);
};
}
if (term.atom)
return this.evalAtom(term.atom);
if (term.assertion) {
return function matcher(x, c) {
var t = self.evalAssertion(term.assertion);
var r = t(x);
return r ? c(x) : MatchResult.FAILURE;
};
}
throw new Error("Unreachable: " + term);
};
ProcedureBuilder.prototype.evalClassEscape = function(ce) {
throw new Error("NYI: " + ce);
};
ProcedureBuilder.prototype.evalClassAtomNoDash = function(cand) {
switch (cand.kind) {
case 'SourceCharacter': return this.CharSet([cand.value]);
case 'ClassEscape': return this.evalClassEscape(cand.value);
default: throw new Error("Unreachable: " + cand.kind);
}
};
ProcedureBuilder.prototype.evalClassAtom = function(ca) {
switch (ca.kind) {
case 'Dash': return this.CharSet(['-']);
case 'NoDash': return this.evalClassAtomNoDash(ca.value);
default: throw new Error("Unreachable: " + ca.kind);
}
};
ProcedureBuilder.prototype.evalNonemptyClassRangesNoDash = function(necrnd) {
switch (necrnd.kind) {
case 'ClassAtom':
return this.evalClassAtom(necrnd.classAtom);
case 'NotDashed':
var A = this.evalClassAtomNoDash(necrnd.classAtom);
var B = this.evalNonemptyClassRangesNoDash(necrnd.value);
return this.CharSetUnion(A, B);
case 'Dashed':
var A = this.evalClassAtomNoDash(necrnd.classAtom);
var B = this.evalClassAtom(necrnd.value[0]);
var C = this.evalClassRanges(necrnd.value[1]);
var D = this.CharacterRange(A, B);
return this.CharSetUnion(D, C);
default:
throw new Error("Unreachable: " + necrnd.kind);
}
};
ProcedureBuilder.prototype.evalNonemptyClassRanges = function(necr) {
var self = this;
if (necr.kind === 'NoDash' && !necr.value)
return self.evalClassAtom(necr.classAtom);
var A = self.evalClassAtom(necr.classAtom);
if (necr.kind === 'NoDash') {
var B = self.evalNonemptyClassRangesNoDash(necr.value);
return self.CharSetUnion(A, B);
}
var otherClassAtom = necr.value[0];
var classRanges = necr.value[1];
var B = self.evalClassAtom(otherClassAtom);
var C = self.evalClassRanges(classRanges);
var D = self.CharacterRange(A, B);
return self.CharSetUnion(D, C);
};
ProcedureBuilder.prototype.evalClassRanges = function(cr) {
if (cr === ClassRanges.EMPTY)
return this.CharSet([]);
return this.evalNonemptyClassRanges(cr.value);
};
ProcedureBuilder.prototype.evalCharacterClass = function(cc) {
var charSet = this.evalClassRanges(cc.ranges);
return {charSet: charSet, inverted: cc.inverted};
};
ProcedureBuilder.prototype.evalCharacterEscape = function(ce) {
switch (ce.kind) {
case 'IdentityEscape':
return ce.value.value;
case 'ControlEscape':
return ce.value;
default:
throw new Error("NYI");
}
};
ProcedureBuilder.prototype.evalCharacterClassEscape = function(cce) {
switch (cce.kind) {
case 'Digit':
return this.CharSet(stringRange(10));
case 'NotDigit':
return this.CharSet(stringRange(10), {inverted: true});
case 'Space':
return this.CharSet([
// whitespace characters
'\u0009', '\u000B', '\u000C', '\u0020', '\u00A0', '\uFEFF',
// line terminator characters
'\u000A', '\u000D', '\u2028', '\u2029'
]);
case 'NotSpace':
throw new Error("NYI");
case 'Word':
return this.CharSet([
'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '_'
]);
case 'NotWord':
throw new Error("NYI");
}
}
ProcedureBuilder.prototype.evalDecimalEscape = function(de) {
var i = parseInt(de.value);
if (i === 0)
return '\0';
return i;
};
ProcedureBuilder.prototype.evalAtomEscape = function(ae) {
var self = this;
if (ae.decimalEscape) {
/* 15.10.2.9 AtomEscape :: DecimalEscape #1 */
var E = self.evalDecimalEscape(ae.decimalEscape);
if (isString(E)) {
var ch = E;
var A = self.CharSet([ch]);
return self.CharacterSetMatcher(A, false);
}
assert(typeof E === 'number');
var n = E;
if (n == 0 || n > self.ast.nCapturingParens)
throw new Error("SyntaxError: bad decimal escape value");
/* 15.10.2.9 AtomEscape :: DecimalEscape #5 */
return function matcher(x, c) {
var cap = x.captures;
var s = cap[n];
if (s === undefined)
return c(x);
var e = x.endIndex;
var len = s.length;
var f = e + len;
if (f > self.inputLength)
return MatchResult.FAILURE;
spec('15.10.2.9 AtomEscape::DecimalEscape 5.8');
for (var i = 0; i < len; ++i) {
if (self.Canonicalize(s[i]) !== self.Canonicalize(self.input[e + i]))
return MatchResult.FAILURE;
}
var y = self.State(f, cap);
return c(y);
};
}
if (ae.characterEscape) {
/* 15.10.2.9 AtomEscape :: CharacterEscape #1 */
var ch = self.evalCharacterEscape(ae.characterEscape);
/* 15.10.2.9 AtomEscape :: CharacterEscape #2 */
var A = self.CharSet([ch]);
/* 15.10.2.9 AtomEscape :: CharacterEscape #3 */
return self.CharacterSetMatcher(A, false);
}
assert(ae.characterClassEscape);
/* 15.10.2.9 AtomEscape :: CharacterClassEscape #1 */
var A = self.evalCharacterClassEscape(ae.characterClassEscape);
/* 15.10.2.9 AtomEscape :: CharacterClassEscape #2 */
return self.CharacterSetMatcher(A, false);
};
ProcedureBuilder.prototype.evalAtom = function ProcedureBuilder__evalAtom(atom) {
var self = this;
self.clog.debug("evaluating atom");
switch (atom.kind) {
case 'PatternCharacter':
var ch = atom.value.sourceCharacter;
return self.CharacterSetMatcher(self.CharSet([ch]), false);
case 'Dot':
return self.CharacterSetMatcher({
has: function(ch) { return ch !== '\n'; },
hasCanonicalized: function(cch) {
return cch !== self.canonicalize('\n');
}
}, false);
case 'CapturingGroup':
var m = self.evalDisjunction(atom.value);
var parenIndex = atom.capturingNumber;
self.checkParenIndex(parenIndex);
return function matcher(x, c) {
var d = function(y) {
self.rlog.info('executing capture group continuation');
var cap = y.captures.map(identity);
var xe = x.endIndex;
var ye = y.endIndex;
self.rlog.debug('start state endIndex: ' + xe);
self.rlog.debug('end state endIndex: ' + ye);
var s = self.input.substr(xe, ye - xe);
cap[parenIndex] = s;
var z = self.State(ye, cap);
//self.rlog.info("executing capture group's subsequent continuation: " + c);
return c(z);
};
return m(x, d);
};
case 'CharacterClass':
var result = self.evalCharacterClass(atom.value);
return self.CharacterSetMatcher(result.charSet, result.inverted);
case 'NonCapturingGroup':
return self.evalDisjunction(atom.value);
case 'AtomEscape':
return self.evalAtomEscape(atom.value);
default:
throw new Error("NYI: " + atom);
}
};
/*********************
* Transform helpers *
*********************/
ProcedureBuilder.prototype.CharacterSetMatcher = function(charSet, invert) {
if (!charSet)
throw new Error("Bad value for charSet: " + charSet);
var self = this;
self.clog.debug("creating char set matcher");
return function matcher(x, c) {
var e = x.endIndex;
// Note: use clog because char set matchers are all executed at compile time.
self.clog.debug("char matcher at end index: " + e);
if (e === self.inputLength)
return MatchResult.FAILURE;
/*
* FIXME: c is both a continuation and character identifier here
* in the spec.
*/
var ch = self.input[e];
var chc = self.canonicalize(ch);
self.clog.debug("canonicalized input char: " + uneval(chc));
self.clog.debug("(to be canonicalized) char set: " + charSet);
if (charSet.hasCanonicalized(chc) === invert)
return MatchResult.FAILURE;
var cap = x.captures;
var y = self.State(e + 1, cap);
return c(y);
};
};
ProcedureBuilder.prototype.isWordChar = function(e) {
var self = this;
if (e === -1 || e === self.inputLength)
return false;
var c = self.input[e];
var co = ord(c);
// Note: spec needs a lowercase a here.
var ranges = [
['a', 'z'],
['A', 'Z'],
['0', '9'],
['_', '_'],
];
for (var i in ranges) {
if (!ranges.hasOwnProperty(i))
continue;
var range = ranges[i];
if (ord(range[0]) <= co && co <= ord(range[1]))
return true;
}
return false;
}
ProcedureBuilder.prototype.repeatMatcher = function(m, min, max, greedy, x, c,
parenIndex, parenCount) {
var self = this;
var spec = self.spec.debug.bind(self.spec);
spec('15.10.2.5 RepeatMatcher 1');
if (max === 0)
return c(x);
var d = function(y) {
spec('15.10.2.5 RepeatMatcher 2.1');
if (min === 0 && y.endIndex === x.endIndex)
return MatchResult.FAILURE;
spec('15.10.2.5 RepeatMatcher 2.2');
var min2 = min === 0 ? 0 : min - 1;
spec('15.10.2.5 RepeatMatcher 2.3');
var max2 = max === Infinity ? Infinity : max - 1;
spec('15.10.2.5 RepeatMatcher 2.4');
return self.repeatMatcher(m, min2, max2, greedy, y, c, parenIndex, parenCount);
};
spec('15.10.2.5 RepeatMatcher 3');
var cap = x.captures.map(identity);
spec('15.10.2.5 RepeatMatcher 4');
self.rlog.debug('clearing parens [' + parenIndex + ', ' + (parenIndex + parenCount) + ')');
if (parenCount)
self.checkParenIndex(parenIndex);
for (var k = parenIndex; k < parenIndex + parenCount; ++k)
cap[k] = undefined;
self.checkCaptures(cap);
spec('15.10.2.5 RepeatMatcher 5');
var e = x.endIndex;
spec('15.10.2.5 RepeatMatcher 6');
var xr = self.State(e, cap);
spec('15.10.2.5 RepeatMatcher 7');
if (min !== 0)
return m(xr, d);
spec('15.10.2.5 RepeatMatcher 8');
if (!greedy) {
var z = c(x);
if (z !== MatchResult.FAILURE)
return z;
return m(xr, d);
}
spec('15.10.2.5 RepeatMatcher 9');
var z = m(xr, d);
spec('15.10.2.5 RepeatMatcher 10');
if (z !== MatchResult.FAILURE)
return z;
spec('15.10.2.5 RepeatMatcher 11');
return c(x);
}
ProcedureBuilder.prototype.canonicalize = function ProcedureBuilder__canonicalize(ch) {
if (!this.ignoreCase)
return ch;
var u = ch.toUpperCase();
if (u.length !== 1) // TODO: is this the correct check?
return u;
var cu = u[0];
return (ch.charCodeAt(0) >= 128 && cu.charCodeAt(0) < 128)
? ch
: cu;
};
ProcedureBuilder.prototype.CharacterRange = function(A, B) {
if (A.length() !== 1 || B.length() !== 1)
throw new SyntaxError("Can't use a set as an endpoint in a character range: "
+ A + ' to ' + B);
var a = A.getOnly();
var b = B.getOnly();
var i = ord(a);
var j = ord(b);
if (i > j)
throw new SyntaxError('Invalid character range: ' + A + ' to ' + B);
var chars = [];
while (i <= j)
chars.push(chr(i++));
return this.CharSet(chars);
};
/* The parenIndex is 1-based. */
ProcedureBuilder.prototype.checkParenIndex = function(parenIndex) {
assert(parenIndex !== undefined);
assert(1 <= parenIndex && parenIndex <= this.nCapturingParens, parenIndex);
};
ProcedureBuilder.prototype.checkCaptures = function(captures) {
/* Array length assumes 0-indexing. */
assert(captures.length === this.nCapturingParens + 1,
captures.length + ' !== ' + (this.nCapturingParens + 1));
assert(typeof captures[0] === 'undefined');
};
ProcedureBuilder.prototype.State = function(endIndex, captures) {
this.checkCaptures(captures);
return {
endIndex: endIndex,
captures: captures
};
};
ProcedureBuilder.prototype._CharSet = function _CharSet(pb, items, options) {
var self = this;
self._inverted = options.inverted || false;
self._set = new Set(items);
// Check it has characters in it.
self._set.each(function (elem) {
assert(elem.length === 1, 'Not a single character: ' + elem);
});
self.hasCanonicalized = function CharSet__hasCanonicalized(tcc) {
var result = self._set.hasWithMap(tcc, pb.canonicalize.bind(pb));
return self._inverted ? !result : result;
};
self.length = function CharSet__length() {
if (self._inverted)
throw new Error("Inverted sets have no length");
return self._set.length();
};
self.getOnly = function CharSet__getOnly() {
if (self._inverted)
throw new Error("Inverted sets do not have a solitary member");
return self._set.getOnly();
};
};
ProcedureBuilder.prototype.CharSet = function CharSet(items, options) {
assert(!(this instanceof CharSet), 'Do not use CharSet as a constructor');
assert(arguments.length <= 2,
'Pass CharSet a single items argument and an optional options argument');
var options = options || {};
var pb = this;
return new this._CharSet(pb, items, options);
};
ProcedureBuilder.prototype.CharSetUnion = function(cs1, cs2) {
var su = cdlre.SetUnion(cs1, cs2);
su.hasCanonicalized = function(tcc) {
return cs1.hasCanonicalized(tcc) || cs2.hasCanonicalized(tcc);
};
return su;
};
/**
* Return a function that accepts an input string and an index, and matches
* that input string from the index using the pattern represented by |ast|.
*/
function CompiledProcedure(ast, multiline, ignoreCase) {
return function(str, index) {
if (index === undefined)
index = 0;
return new ProcedureBuilder(ast, multiline, ignoreCase, str, index).evalPattern();
};
}
return extend(cdlre, {
CompiledProcedure: CompiledProcedure,
MatchResult: MatchResult,
});
})(cdlre);