esprima
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ECMAScript parsing infrastructure for multipurpose analysis
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JavaScript
/* -*- Mode: JS; tab-width: 4; indent-tabs-mode: nil; -*-
* vim: set sw=4 ts=4 et tw=78:
* ***** BEGIN LICENSE BLOCK *****
*
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is the Narcissus JavaScript engine.
*
* The Initial Developer of the Original Code is
* Brendan Eich <brendan@mozilla.org>.
* Portions created by the Initial Developer are Copyright (C) 2004
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Tom Austin <taustin@ucsc.edu>
* Brendan Eich <brendan@mozilla.org>
* Shu-Yu Guo <shu@rfrn.org>
* Dave Herman <dherman@mozilla.com>
* Dimitris Vardoulakis <dimvar@ccs.neu.edu>
* Patrick Walton <pcwalton@mozilla.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* Narcissus - JS implemented in JS.
*
* Parser.
*/
Narcissus.parser = (function() {
var lexer = Narcissus.lexer;
var definitions = Narcissus.definitions;
const StringMap = definitions.StringMap;
const Stack = definitions.Stack;
// Set constants in the local scope.
eval(definitions.consts);
// Banned statement types by language version.
const blackLists = { 160: {}, 185: {}, harmony: {} };
blackLists[160][IMPORT] = true;
blackLists[160][EXPORT] = true;
blackLists[160][LET] = true;
blackLists[160][MODULE] = true;
blackLists[160][YIELD] = true;
blackLists[185][IMPORT] = true;
blackLists[185][EXPORT] = true;
blackLists[185][MODULE] = true;
blackLists.harmony[WITH] = true;
/*
* pushDestructuringVarDecls :: (node, hoisting node) -> void
*
* Recursively add all destructured declarations to varDecls.
*/
function pushDestructuringVarDecls(n, s) {
for (var i in n) {
var sub = n[i];
if (sub.type === IDENTIFIER) {
s.varDecls.push(sub);
} else {
pushDestructuringVarDecls(sub, s);
}
}
}
function StaticContext(parentScript, parentBlock, inModule, inFunction) {
this.parentScript = parentScript;
this.parentBlock = parentBlock || parentScript;
this.inModule = inModule || false;
this.inFunction = inFunction || false;
this.inForLoopInit = false;
this.topLevel = true;
this.allLabels = new Stack();
this.currentLabels = new Stack();
this.labeledTargets = new Stack();
this.defaultLoopTarget = null;
this.defaultTarget = null;
this.blackList = blackLists[Narcissus.options.version];
Narcissus.options.ecma3OnlyMode && (this.ecma3OnlyMode = true);
Narcissus.options.parenFreeMode && (this.parenFreeMode = true);
}
StaticContext.prototype = {
ecma3OnlyMode: false,
parenFreeMode: false,
// non-destructive update via prototype extension
update: function(ext) {
var desc = {};
for (var key in ext) {
desc[key] = {
value: ext[key],
writable: true,
enumerable: true,
configurable: true
}
}
return Object.create(this, desc);
},
pushLabel: function(label) {
return this.update({ currentLabels: this.currentLabels.push(label),
allLabels: this.allLabels.push(label) });
},
pushTarget: function(target) {
var isDefaultLoopTarget = target.isLoop;
var isDefaultTarget = isDefaultLoopTarget || target.type === SWITCH;
if (this.currentLabels.isEmpty()) {
if (isDefaultLoopTarget) this.update({ defaultLoopTarget: target });
if (isDefaultTarget) this.update({ defaultTarget: target });
return this;
}
target.labels = new StringMap();
this.currentLabels.forEach(function(label) {
target.labels.set(label, true);
});
return this.update({ currentLabels: new Stack(),
labeledTargets: this.labeledTargets.push(target),
defaultLoopTarget: isDefaultLoopTarget
? target
: this.defaultLoopTarget,
defaultTarget: isDefaultTarget
? target
: this.defaultTarget });
},
nest: function() {
return this.topLevel ? this.update({ topLevel: false }) : this;
},
allow: function(type) {
switch (type) {
case EXPORT:
if (!this.inModule || this.inFunction || !this.topLevel)
return false;
// FALL THROUGH
case IMPORT:
return !this.inFunction && this.topLevel;
case MODULE:
return !this.inFunction && this.topLevel;
default:
return true;
}
}
};
/*
* Script :: (tokenizer, boolean, boolean) -> node
*
* Parses the toplevel and module/function bodies.
*/
function Script(t, inModule, inFunction) {
var n = new Node(t, scriptInit());
Statements(t, new StaticContext(n, n, inModule, inFunction), n);
return n;
}
// We extend Array slightly with a top-of-stack method.
definitions.defineProperty(Array.prototype, "top",
function() {
return this.length && this[this.length-1];
}, false, false, true);
/*
* Node :: (tokenizer, optional init object) -> node
*/
function Node(t, init) {
var token = t.token;
if (token) {
// If init.type exists it will override token.type.
this.type = token.type;
this.value = token.value;
this.lineno = token.lineno;
// Start and end are file positions for error handling.
this.start = token.start;
this.end = token.end;
} else {
this.lineno = t.lineno;
}
// Node uses a tokenizer for debugging (getSource, filename getter).
this.tokenizer = t;
this.children = [];
for (var prop in init)
this[prop] = init[prop];
}
/*
* SyntheticNode :: (tokenizer, optional init object) -> node
*/
function SyntheticNode(t, init) {
// print("SYNTHETIC NODE");
// if (init.type === COMMA) {
// print("SYNTHETIC COMMA");
// print(init);
// }
this.tokenizer = t;
this.children = [];
for (var prop in init)
this[prop] = init[prop];
this.synthetic = true;
}
var Np = Node.prototype = SyntheticNode.prototype = {};
Np.constructor = Node;
const TO_SOURCE_SKIP = {
type: true,
value: true,
lineno: true,
start: true,
end: true,
tokenizer: true,
assignOp: true
};
function unevalableConst(code) {
var token = definitions.tokens[code];
var constName = definitions.opTypeNames.hasOwnProperty(token)
? definitions.opTypeNames[token]
: token in definitions.keywords
? token.toUpperCase()
: token;
return { toSource: function() { return constName } };
}
Np.toSource = function toSource() {
var mock = {};
var self = this;
mock.type = unevalableConst(this.type);
// avoid infinite recursion in case of back-links
if (this.generatingSource)
return mock.toSource();
this.generatingSource = true;
if ("value" in this)
mock.value = this.value;
if ("lineno" in this)
mock.lineno = this.lineno;
if ("start" in this)
mock.start = this.start;
if ("end" in this)
mock.end = this.end;
if (this.assignOp)
mock.assignOp = unevalableConst(this.assignOp);
for (var key in this) {
if (this.hasOwnProperty(key) && !(key in TO_SOURCE_SKIP))
mock[key] = this[key];
}
try {
return mock.toSource();
} finally {
delete this.generatingSource;
}
};
// Always use push to add operands to an expression, to update start and end.
Np.push = function (kid) {
// kid can be null e.g. [1, , 2].
if (kid !== null) {
if (kid.start < this.start)
this.start = kid.start;
if (this.end < kid.end)
this.end = kid.end;
}
return this.children.push(kid);
}
Node.indentLevel = 0;
function tokenString(tt) {
var t = definitions.tokens[tt];
return /^\W/.test(t) ? definitions.opTypeNames[t] : t.toUpperCase();
}
Np.toString = function () {
var a = [];
for (var i in this) {
if (this.hasOwnProperty(i) && i !== 'type' && i !== 'target')
a.push({id: i, value: this[i]});
}
a.sort(function (a,b) { return (a.id < b.id) ? -1 : 1; });
const INDENTATION = " ";
var n = ++Node.indentLevel;
var s = "{\n" + INDENTATION.repeat(n) + "type: " + tokenString(this.type);
for (i = 0; i < a.length; i++)
s += ",\n" + INDENTATION.repeat(n) + a[i].id + ": " + a[i].value;
n = --Node.indentLevel;
s += "\n" + INDENTATION.repeat(n) + "}";
return s;
}
Np.getSource = function () {
return this.tokenizer.source.slice(this.start, this.end);
};
Np.synth = function(init) {
var node = new SyntheticNode(this.tokenizer, init);
node.filename = this.filename;
node.lineno = this.lineno;
node.start = this.start;
node.end = this.end;
return node;
};
/*
* Helper init objects for common nodes.
*/
const LOOP_INIT = { isLoop: true };
function blockInit() {
return { type: BLOCK, varDecls: [] };
}
function scriptInit() {
return { type: SCRIPT,
funDecls: [],
varDecls: [],
modDefns: new StringMap(),
modAssns: new StringMap(),
modDecls: new StringMap(),
modLoads: new StringMap(),
impDecls: [],
expDecls: [],
exports: new StringMap(),
hasEmptyReturn: false,
hasReturnWithValue: false,
isGenerator: false };
}
definitions.defineGetter(Np, "filename",
function() {
return this.tokenizer.filename;
});
definitions.defineGetter(Np, "length",
function() {
throw new Error("Node.prototype.length is gone; " +
"use n.children.length instead");
});
definitions.defineProperty(String.prototype, "repeat",
function(n) {
var s = "", t = this + s;
while (--n >= 0)
s += t;
return s;
}, false, false, true);
function MaybeLeftParen(t, x) {
if (x.parenFreeMode)
return t.match(LEFT_PAREN) ? LEFT_PAREN : END;
return t.mustMatch(LEFT_PAREN).type;
}
function MaybeRightParen(t, p) {
if (p === LEFT_PAREN)
t.mustMatch(RIGHT_PAREN);
}
/*
* Statements :: (tokenizer, compiler context, node) -> void
*
* Parses a sequence of Statements.
*/
function Statements(t, x, n) {
try {
while (!t.done && t.peek(true) !== RIGHT_CURLY)
n.push(Statement(t, x));
} catch (e) {
if (t.done)
t.unexpectedEOF = true;
throw e;
}
}
function Block(t, x) {
t.mustMatch(LEFT_CURLY);
var n = new Node(t, blockInit());
Statements(t, x.update({ parentBlock: n }).pushTarget(n), n);
t.mustMatch(RIGHT_CURLY);
return n;
}
const DECLARED_FORM = 0, EXPRESSED_FORM = 1, STATEMENT_FORM = 2;
/*
* Export :: (binding node, boolean) -> Export
*
* Static semantic representation of a module export.
*/
function Export(node, isDefinition) {
this.node = node; // the AST node declaring this individual export
this.isDefinition = isDefinition; // is the node an 'export'-annotated definition?
this.resolved = null; // resolved pointer to the target of this export
}
/*
* registerExport :: (StringMap, EXPORT node) -> void
*/
function registerExport(exports, decl) {
function register(name, exp) {
if (exports.has(name))
throw new SyntaxError("multiple exports of " + name);
exports.set(name, exp);
}
switch (decl.type) {
case MODULE:
case FUNCTION:
register(decl.name, new Export(decl, true));
break;
case VAR:
for (var i = 0; i < decl.children.length; i++)
register(decl.children[i].name, new Export(decl.children[i], true));
break;
case LET:
case CONST:
throw new Error("NYI: " + definitions.tokens[decl.type]);
case EXPORT:
for (var i = 0; i < decl.pathList.length; i++) {
var path = decl.pathList[i];
switch (path.type) {
case OBJECT_INIT:
for (var j = 0; j < path.children.length; j++) {
// init :: IDENTIFIER | PROPERTY_INIT
var init = path.children[j];
if (init.type === IDENTIFIER)
register(init.value, new Export(init, false));
else
register(init.children[0].value, new Export(init.children[1], false));
}
break;
case DOT:
register(path.children[1].value, new Export(path, false));
break;
case IDENTIFIER:
register(path.value, new Export(path, false));
break;
default:
throw new Error("unexpected export path: " + definitions.tokens[path.type]);
}
}
break;
default:
throw new Error("unexpected export decl: " + definitions.tokens[exp.type]);
}
}
/*
* Module :: (node) -> Module
*
* Static semantic representation of a module.
*/
function Module(node) {
var exports = node.body.exports;
var modDefns = node.body.modDefns;
var exportedModules = new StringMap();
exports.forEach(function(name, exp) {
var node = exp.node;
if (node.type === MODULE) {
exportedModules.set(name, node);
} else if (!exp.isDefinition && node.type === IDENTIFIER && modDefns.has(node.value)) {
var mod = modDefns.get(node.value);
exportedModules.set(name, mod);
}
});
this.node = node;
this.exports = exports;
this.exportedModules = exportedModules;
}
/*
* Statement :: (tokenizer, compiler context) -> node
*
* Parses a Statement.
*/
function Statement(t, x) {
var i, label, n, n2, p, c, ss, tt = t.get(true), tt2, x2, x3;
var comments = t.blockComments;
if (x.blackList[tt])
throw t.newSyntaxError(definitions.tokens[tt] + " statements only allowed in Harmony");
if (!x.allow(tt))
throw t.newSyntaxError(definitions.tokens[tt] + " statement in illegal context");
// Cases for statements ending in a right curly return early, avoiding the
// common semicolon insertion magic after this switch.
switch (tt) {
case IMPORT:
n = new Node(t);
n.pathList = ImportPathList(t, x);
x.parentScript.impDecls.push(n);
break;
case EXPORT:
switch (t.peek()) {
case MODULE:
case FUNCTION:
case LET:
case VAR:
case CONST:
n = Statement(t, x);
n.blockComments = comments;
n.exported = true;
x.parentScript.expDecls.push(n);
registerExport(x.parentScript.exports, n);
return n;
default:
n = new Node(t);
n.pathList = ExportPathList(t, x);
break;
}
x.parentScript.expDecls.push(n);
registerExport(x.parentScript.exports, n);
break;
case MODULE:
n = new Node(t);
n.blockComments = comments;
t.mustMatch(IDENTIFIER);
label = t.token.value;
if (t.match(LEFT_CURLY)) {
n.name = label;
n.body = Script(t, true, false);
n.module = new Module(n);
t.mustMatch(RIGHT_CURLY);
x.parentScript.modDefns.set(n.name, n);
return n;
}
t.unget();
ModuleVariables(t, x, n);
return n;
case FUNCTION:
// DECLARED_FORM extends funDecls of x, STATEMENT_FORM doesn't.
return FunctionDefinition(t, x, true, x.topLevel ? DECLARED_FORM : STATEMENT_FORM, comments);
case LEFT_CURLY:
n = new Node(t, blockInit());
Statements(t, x.update({ parentBlock: n }).pushTarget(n).nest(), n);
t.mustMatch(RIGHT_CURLY);
return n;
case IF:
n = new Node(t);
n.condition = HeadExpression(t, x);
x2 = x.pushTarget(n).nest();
n.thenPart = Statement(t, x2);
n.elsePart = t.match(ELSE, true) ? Statement(t, x2) : null;
return n;
case SWITCH:
// This allows CASEs after a DEFAULT, which is in the standard.
n = new Node(t, { cases: [], defaultIndex: -1 });
n.discriminant = HeadExpression(t, x);
x2 = x.pushTarget(n).nest();
t.mustMatch(LEFT_CURLY);
while ((tt = t.get()) !== RIGHT_CURLY) {
switch (tt) {
case DEFAULT:
if (n.defaultIndex >= 0)
throw t.newSyntaxError("More than one switch default");
// FALL THROUGH
case CASE:
n2 = new Node(t);
if (tt === DEFAULT)
n.defaultIndex = n.cases.length;
else
n2.caseLabel = Expression(t, x2, COLON);
break;
default:
throw t.newSyntaxError("Invalid switch case");
}
t.mustMatch(COLON);
n2.statements = new Node(t, blockInit());
while ((tt=t.peek(true)) !== CASE && tt !== DEFAULT &&
tt !== RIGHT_CURLY)
n2.statements.push(Statement(t, x2));
n.cases.push(n2);
}
return n;
case FOR:
n = new Node(t, LOOP_INIT);
n.blockComments = comments;
if (t.match(IDENTIFIER)) {
if (t.token.value === "each")
n.isEach = true;
else
t.unget();
}
if (!x.parenFreeMode)
t.mustMatch(LEFT_PAREN);
x2 = x.pushTarget(n).nest();
x3 = x.update({ inForLoopInit: true });
n2 = null;
if ((tt = t.peek(true)) !== SEMICOLON) {
if (tt === VAR || tt === CONST) {
t.get();
n2 = Variables(t, x3);
} else if (tt === LET) {
t.get();
if (t.peek() === LEFT_PAREN) {
n2 = LetBlock(t, x3, false);
} else {
// Let in for head, we need to add an implicit block
// around the rest of the for.
x3.parentBlock = n;
n.varDecls = [];
n2 = Variables(t, x3);
}
} else {
n2 = Expression(t, x3);
}
}
if (n2 && t.match(IN)) {
n.type = FOR_IN;
n.object = Expression(t, x3);
if (n2.type === VAR || n2.type === LET) {
c = n2.children;
// Destructuring turns one decl into multiples, so either
// there must be only one destructuring or only one
// decl.
if (c.length !== 1 && n2.destructurings.length !== 1) {
throw new SyntaxError("Invalid for..in left-hand side",
t.filename, n2.lineno);
}
if (n2.destructurings.length > 0) {
n.iterator = n2.destructurings[0];
} else {
n.iterator = c[0];
}
n.varDecl = n2;
} else {
if (n2.type === ARRAY_INIT || n2.type === OBJECT_INIT) {
n2.destructuredNames = checkDestructuring(t, x3, n2);
}
n.iterator = n2;
}
} else {
x3.inForLoopInit = false;
n.setup = n2;
t.mustMatch(SEMICOLON);
if (n.isEach)
throw t.newSyntaxError("Invalid for each..in loop");
n.condition = (t.peek(true) === SEMICOLON)
? null
: Expression(t, x3);
t.mustMatch(SEMICOLON);
tt2 = t.peek(true);
n.update = (x.parenFreeMode
? tt2 === LEFT_CURLY || definitions.isStatementStartCode[tt2]
: tt2 === RIGHT_PAREN)
? null
: Expression(t, x3);
}
if (!x.parenFreeMode)
t.mustMatch(RIGHT_PAREN);
n.body = Statement(t, x2);
return n;
case WHILE:
n = new Node(t, { isLoop: true });
n.blockComments = comments;
n.condition = HeadExpression(t, x);
n.body = Statement(t, x.pushTarget(n).nest());
return n;
case DO:
n = new Node(t, { isLoop: true });
n.blockComments = comments;
n.body = Statement(t, x.pushTarget(n).nest());
t.mustMatch(WHILE);
n.condition = HeadExpression(t, x);
if (!x.ecmaStrictMode) {
// <script language="JavaScript"> (without version hints) may need
// automatic semicolon insertion without a newline after do-while.
// See http://bugzilla.mozilla.org/show_bug.cgi?id=238945.
t.match(SEMICOLON);
return n;
}
break;
case BREAK:
case CONTINUE:
n = new Node(t);
n.blockComments = comments;
// handle the |foo: break foo;| corner case
x2 = x.pushTarget(n);
if (t.peekOnSameLine() === IDENTIFIER) {
t.get();
n.label = t.token.value;
}
if (n.label) {
n.target = x2.labeledTargets.find(function(target) { return target.labels.has(n.label) });
} else if (tt === CONTINUE) {
n.target = x2.defaultLoopTarget;
} else {
n.target = x2.defaultTarget;
}
if (!n.target)
throw t.newSyntaxError("Invalid " + ((tt === BREAK) ? "break" : "continue"));
if (!n.target.isLoop && tt === CONTINUE)
throw t.newSyntaxError("Invalid continue");
break;
case TRY:
n = new Node(t, { catchClauses: [] });
n.blockComments = comments;
n.tryBlock = Block(t, x);
while (t.match(CATCH)) {
n2 = new Node(t);
p = MaybeLeftParen(t, x);
switch (t.get()) {
case LEFT_BRACKET:
case LEFT_CURLY:
// Destructured catch identifiers.
t.unget();
n2.varName = DestructuringExpression(t, x, true);
break;
case IDENTIFIER:
n2.varName = t.token.value;
break;
default:
throw t.newSyntaxError("missing identifier in catch");
break;
}
if (t.match(IF)) {
if (x.ecma3OnlyMode)
throw t.newSyntaxError("Illegal catch guard");
if (n.catchClauses.length && !n.catchClauses.top().guard)
throw t.newSyntaxError("Guarded catch after unguarded");
n2.guard = Expression(t, x);
}
MaybeRightParen(t, p);
n2.block = Block(t, x);
n.catchClauses.push(n2);
}
if (t.match(FINALLY))
n.finallyBlock = Block(t, x);
if (!n.catchClauses.length && !n.finallyBlock)
throw t.newSyntaxError("Invalid try statement");
return n;
case CATCH:
case FINALLY:
throw t.newSyntaxError(definitions.tokens[tt] + " without preceding try");
case THROW:
n = new Node(t);
n.exception = Expression(t, x);
break;
case RETURN:
n = ReturnOrYield(t, x);
break;
case WITH:
n = new Node(t);
n.blockComments = comments;
n.object = HeadExpression(t, x);
n.body = Statement(t, x.pushTarget(n).nest());
return n;
case VAR:
case CONST:
n = Variables(t, x);
break;
case LET:
if (t.peek() === LEFT_PAREN)
n = LetBlock(t, x, true);
else
n = Variables(t, x);
break;
case DEBUGGER:
n = new Node(t);
break;
case NEWLINE:
case SEMICOLON:
n = new Node(t, { type: SEMICOLON });
n.blockComments = comments;
n.expression = null;
return n;
default:
if (tt === IDENTIFIER) {
tt = t.peek();
// Labeled statement.
if (tt === COLON) {
label = t.token.value;
if (x.allLabels.has(label))
throw t.newSyntaxError("Duplicate label");
t.get();
n = new Node(t, { type: LABEL, label: label });
n.blockComments = comments;
n.statement = Statement(t, x.pushLabel(label).nest());
n.target = (n.statement.type === LABEL) ? n.statement.target : n.statement;
return n;
}
}
// Expression statement.
// We unget the current token to parse the expression as a whole.
n = new Node(t, { type: SEMICOLON });
t.unget();
n.blockComments = comments;
n.expression = Expression(t, x);
n.end = n.expression.end;
break;
}
n.blockComments = comments;
MagicalSemicolon(t);
return n;
}
/*
* MagicalSemicolon :: (tokenizer) -> void
*/
function MagicalSemicolon(t) {
var tt;
if (t.lineno === t.token.lineno) {
tt = t.peekOnSameLine();
if (tt !== END && tt !== NEWLINE && tt !== SEMICOLON && tt !== RIGHT_CURLY)
throw t.newSyntaxError("missing ; before statement");
}
t.match(SEMICOLON);
}
/*
* ReturnOrYield :: (tokenizer, compiler context) -> (RETURN | YIELD) node
*/
function ReturnOrYield(t, x) {
var n, b, tt = t.token.type, tt2;
var parentScript = x.parentScript;
if (tt === RETURN) {
if (!x.inFunction)
throw t.newSyntaxError("Return not in function");
} else /* if (tt === YIELD) */ {
if (!x.inFunction)
throw t.newSyntaxError("Yield not in function");
parentScript.isGenerator = true;
}
n = new Node(t, { value: undefined });
tt2 = (tt === RETURN) ? t.peekOnSameLine(true) : t.peek(true);
if (tt2 !== END && tt2 !== NEWLINE &&
tt2 !== SEMICOLON && tt2 !== RIGHT_CURLY
&& (tt !== YIELD ||
(tt2 !== tt && tt2 !== RIGHT_BRACKET && tt2 !== RIGHT_PAREN &&
tt2 !== COLON && tt2 !== COMMA))) {
if (tt === RETURN) {
n.value = Expression(t, x);
parentScript.hasReturnWithValue = true;
} else {
n.value = AssignExpression(t, x);
}
} else if (tt === RETURN) {
parentScript.hasEmptyReturn = true;
}
// Disallow return v; in generator.
if (parentScript.hasReturnWithValue && parentScript.isGenerator)
throw t.newSyntaxError("Generator returns a value");
return n;
}
/*
* ModuleExpression :: (tokenizer, compiler context) -> (STRING | IDENTIFIER | DOT) node
*/
function ModuleExpression(t, x) {
return t.match(STRING) ? new Node(t) : QualifiedPath(t, x);
}
/*
* ImportPathList :: (tokenizer, compiler context) -> Array[DOT node]
*/
function ImportPathList(t, x) {
var a = [];
do {
a.push(ImportPath(t, x));
} while (t.match(COMMA));
return a;
}
/*
* ImportPath :: (tokenizer, compiler context) -> DOT node
*/
function ImportPath(t, x) {
var n = QualifiedPath(t, x);
if (!t.match(DOT)) {
if (n.type === IDENTIFIER)
throw t.newSyntaxError("cannot import local variable");
return n;
}
var n2 = new Node(t);
n2.push(n);
n2.push(ImportSpecifierSet(t, x));
return n2;
}
/*
* ExplicitSpecifierSet :: (tokenizer, compiler context, (tokenizer, compiler context) -> node)
* -> OBJECT_INIT node
*/
function ExplicitSpecifierSet(t, x, SpecifierRHS) {
var n, n2, id, tt;
n = new Node(t, { type: OBJECT_INIT });
t.mustMatch(LEFT_CURLY);
if (!t.match(RIGHT_CURLY)) {
do {
id = Identifier(t, x);
if (t.match(COLON)) {
n2 = new Node(t, { type: PROPERTY_INIT });
n2.push(id);
n2.push(SpecifierRHS(t, x));
n.push(n2);
} else {
n.push(id);
}
} while (!t.match(RIGHT_CURLY) && t.mustMatch(COMMA));
}
return n;
}
/*
* ImportSpecifierSet :: (tokenizer, compiler context) -> (IDENTIFIER | OBJECT_INIT) node
*/
function ImportSpecifierSet(t, x) {
return t.match(MUL)
? new Node(t, { type: IDENTIFIER, name: "*" })
: ExplicitSpecifierSet(t, x, Identifier);
}
/*
* Identifier :: (tokenizer, compiler context) -> IDENTIFIER node
*/
function Identifier(t, x) {
t.mustMatch(IDENTIFIER);
return new Node(t, { type: IDENTIFIER });
}
/*
* IdentifierName :: (tokenizer) -> IDENTIFIER node
*/
function IdentifierName(t) {
t.mustMatch(IDENTIFIER, true);
return new Node(t, { type: IDENTIFIER });
}
/*
* QualifiedPath :: (tokenizer, compiler context) -> (IDENTIFIER | DOT) node
*/
function QualifiedPath(t, x) {
var n, n2;
n = Identifier(t, x);
while (t.match(DOT)) {
if (t.peek() !== IDENTIFIER) {
// Unget the '.' token, which isn't part of the QualifiedPath.
t.unget();
break;
}
n2 = new Node(t);
n2.push(n);
n2.push(Identifier(t, x));
n = n2;
}
return n;
}
/*
* ExportPath :: (tokenizer, compiler context) -> (IDENTIFIER | DOT | OBJECT_INIT) node
*/
function ExportPath(t, x) {
if (t.peek() === LEFT_CURLY)
return ExplicitSpecifierSet(t, x, QualifiedPath);
return QualifiedPath(t, x);
}
/*
* ExportPathList :: (tokenizer, compiler context)
* -> Array[(IDENTIFIER | DOT | OBJECT_INIT) node]
*/
function ExportPathList(t, x) {
var a = [];
do {
a.push(ExportPath(t, x));
} while (t.match(COMMA));
return a;
}
/*
* FunctionDefinition :: (tokenizer, compiler context, boolean,
* DECLARED_FORM or EXPRESSED_FORM or STATEMENT_FORM,
* [string] or null or undefined)
* -> node
*/
function FunctionDefinition(t, x, requireName, functionForm, comments) {
var tt;
var f = new Node(t, { params: [], paramComments: [] });
if (typeof comment === "undefined")
comment = null;
f.blockComments = comments;
if (f.type !== FUNCTION)
f.type = (f.value === "get") ? GETTER : SETTER;
if (t.match(IDENTIFIER, false, true))
f.name = t.token.value;
else if (requireName)
throw t.newSyntaxError("missing function identifier");
var inModule = x ? x.inModule : false;
var x2 = new StaticContext(null, null, inModule, true);
t.mustMatch(LEFT_PAREN);
if (!t.match(RIGHT_PAREN)) {
do {
tt = t.get();
f.paramComments.push(t.lastBlockComment());
switch (tt) {
case LEFT_BRACKET:
case LEFT_CURLY:
// Destructured formal parameters.
t.unget();
f.params.push(DestructuringExpression(t, x2));
break;
case IDENTIFIER:
f.params.push(t.token.value);
break;
default:
throw t.newSyntaxError("missing formal parameter");
break;
}
} while (t.match(COMMA));
t.mustMatch(RIGHT_PAREN);
}
// Do we have an expression closure or a normal body?
tt = t.get(true);
if (tt !== LEFT_CURLY)
t.unget();
if (tt !== LEFT_CURLY) {
f.body = AssignExpression(t, x2);
if (f.body.isGenerator)
throw t.newSyntaxError("Generator returns a value");
} else {
f.body = Script(t, inModule, true);
}
if (tt === LEFT_CURLY)
t.mustMatch(RIGHT_CURLY);
f.end = t.token.end;
f.functionForm = functionForm;
if (functionForm === DECLARED_FORM)
x.parentScript.funDecls.push(f);
return f;
}
/*
* ModuleVariables :: (tokenizer, compiler context, MODULE node) -> void
*
* Parses a comma-separated list of module declarations (and maybe
* initializations).
*/
function ModuleVariables(t, x, n) {
var n1, n2;
do {
n1 = Identifier(t, x);
if (t.match(ASSIGN)) {
n2 = ModuleExpression(t, x);
n1.initializer = n2;
if (n2.type === STRING)
x.parentScript.modLoads.set(n1.value, n2.value);
else
x.parentScript.modAssns.set(n1.value, n1);
}
n.push(n1);
} while (t.match(COMMA));
}
/*
* Variables :: (tokenizer, compiler context) -> node
*
* Parses a comma-separated list of var declarations (and maybe
* initializations).
*/
function Variables(t, x, letBlock) {
var n, n2, ss, i, s, tt;
tt = t.token.type;
switch (tt) {
case VAR:
case CONST:
s = x.parentScript;
break;
case LET:
s = x.parentBlock;
break;
case LEFT_PAREN:
tt = LET;
s = letBlock;
break;
}
n = new Node(t, { type: tt, destructurings: [] });
do {
tt = t.get();
if (tt === LEFT_BRACKET || tt === LEFT_CURLY) {
// Need to unget to parse the full destructured expression.
t.unget();
var dexp = DestructuringExpression(t, x, true);
n2 = new Node(t, { type: IDENTIFIER,
name: dexp,
readOnly: n.type === CONST });
n.push(n2);
pushDestructuringVarDecls(n2.name.destructuredNames, s);
n.destructurings.push({ exp: dexp, decl: n2 });
if (x.inForLoopInit && t.peek() === IN) {
continue;
}
t.mustMatch(ASSIGN);
if (t.token.assignOp)
throw t.newSyntaxError("Invalid variable initialization");
n2.blockComment = t.lastBlockComment();
n2.initializer = AssignExpression(t, x);
continue;
}
if (tt !== IDENTIFIER)
throw t.newSyntaxError("missing variable name");
n2 = new Node(t, { type: IDENTIFIER,
name: t.token.value,
readOnly: n.type === CONST });
n.push(n2);
s.varDecls.push(n2);
if (t.match(ASSIGN)) {
var comment = t.lastBlockComment();
if (t.token.assignOp)
throw t.newSyntaxError("Invalid variable initialization");
n2.initializer = AssignExpression(t, x);
} else {
var comment = t.lastBlockComment();
}
n2.blockComment = comment;
} while (t.match(COMMA));
return n;
}
/*
* LetBlock :: (tokenizer, compiler context, boolean) -> node
*
* Does not handle let inside of for loop init.
*/
function LetBlock(t, x, isStatement) {
var n, n2;
// t.token.type must be LET
n = new Node(t, { type: LET_BLOCK, varDecls: [] });
t.mustMatch(LEFT_PAREN);
n.variables = Variables(t, x, n);
t.mustMatch(RIGHT_PAREN);
if (isStatement && t.peek() !== LEFT_CURLY) {
/*
* If this is really an expression in let statement guise, then we
* need to wrap the LET_BLOCK node in a SEMICOLON node so that we pop
* the return value of the expression.
*/
n2 = new Node(t, { type: SEMICOLON,
expression: n });
isStatement = false;
}
if (isStatement)
n.block = Block(t, x);
else
n.expression = AssignExpression(t, x);
return n;
}
function checkDestructuring(t, x, n, simpleNamesOnly) {
if (n.type === ARRAY_COMP)
throw t.newSyntaxError("Invalid array comprehension left-hand side");
if (n.type !== ARRAY_INIT && n.type !== OBJECT_INIT)
return;
var lhss = {};
var nn, n2, idx, sub, cc, c = n.children;
for (var i = 0, j = c.length; i < j; i++) {
if (!(nn = c[i]))
continue;
if (nn.type === PROPERTY_INIT) {
cc = nn.children;
sub = cc[1];
idx = cc[0].value;
} else if (n.type === OBJECT_INIT) {
// Do we have destructuring shorthand {foo, bar}?
sub = nn;
idx = nn.value;
} else {
sub = nn;
idx = i;
}
if (sub.type === ARRAY_INIT || sub.type === OBJECT_INIT) {
lhss[idx] = checkDestructuring(t, x, sub, simpleNamesOnly);
} else {
if (simpleNamesOnly && sub.type !== IDENTIFIER) {
// In declarations, lhs must be simple names
throw t.newSyntaxError("missing name in pattern");
}
lhss[idx] = sub;
}
}
return lhss;
}
function DestructuringExpression(t, x, simpleNamesOnly) {
var n = PrimaryExpression(t, x);
// Keep the list of lefthand sides for varDecls
n.destructuredNames = checkDestructuring(t, x, n, simpleNamesOnly);
return n;
}
function GeneratorExpression(t, x, e) {
return new Node(t, { type: GENERATOR,
expression: e,
tail: ComprehensionTail(t, x) });
}
function ComprehensionTail(t, x) {
var body, n, n2, n3, p;
// t.token.type must be FOR
body = new Node(t, { type: COMP_TAIL });
do {
// Comprehension tails are always for..in loops.
n = new Node(t, { type: FOR_IN, isLoop: true });
if (t.match(IDENTIFIER)) {
// But sometimes they're for each..in.
if (t.token.value === "each")
n.isEach = true;
else
t.unget();
}
p = MaybeLeftParen(t, x);
switch(t.get()) {
case LEFT_BRACKET:
case LEFT_CURLY:
t.unget();
// Destructured left side of for in comprehension tails.
n.iterator = DestructuringExpression(t, x);
break;
case IDENTIFIER:
n.iterator = n3 = new Node(t, { type: IDENTIFIER });
n3.name = n3.value;
n.varDecl = n2 = new Node(t, { type: VAR });
n2.push(n3);
x.parentScript.varDecls.push(n3);
// Don't add to varDecls since the semantics of comprehensions is
// such that the variables are in their own function when
// desugared.
break;
default:
throw t.newSyntaxError("missing identifier");
}
t.mustMatch(IN);
n.object = Expression(t, x);
MaybeRightParen(t, p);
body.push(n);
} while (t.match(FOR));
// Optional guard.
if (t.match(IF))
body.guard = HeadExpression(t, x);
return body;
}
function HeadExpression(t, x) {
var p = MaybeLeftParen(t, x);
var n = ParenExpression(t, x);
MaybeRightParen(t, p);
if (p === END && !n.parenthesized) {
var tt = t.peek();
if (tt !== LEFT_CURLY && !definitions.isStatementStartCode[tt])
throw t.newSyntaxError("Unparenthesized head followed by unbraced body");
}
return n;
}
function ParenExpression(t, x) {
// Always accept the 'in' operator in a parenthesized expression,
// where it's unambiguous, even if we might be parsing the init of a
// for statement.
var n = Expression(t, x.update({ inForLoopInit: x.inForLoopInit &&
(t.token.type === LEFT_PAREN) }));
if (t.match(FOR)) {
if (n.type === YIELD && !n.parenthesized)
throw t.newSyntaxError("Yield expression must be parenthesized");
if (n.type === COMMA && !n.parenthesized)
throw t.newSyntaxError("Generator expression must be parenthesized");
n = GeneratorExpression(t, x, n);
}
return n;
}
/*
* Expression :: (tokenizer, compiler context) -> node
*
* Top-down expression parser matched against SpiderMonkey.
*/
function Expression(t, x) {
var n, n2;
n = AssignExpression(t, x);
if (t.match(COMMA)) {
n2 = new Node(t, { type: COMMA });
n2.push(n);
n = n2;
do {
n2 = n.children[n.children.length-1];
if (n2.type === YIELD && !n2.parenthesized)
throw t.newSyntaxError("Yield expression must be parenthesized");
n.push(AssignExpression(t, x));
} while (t.match(COMMA));
}
return n;
}
function AssignExpression(t, x) {
var n, lhs;
// Have to treat yield like an operand because it could be the leftmost
// operand of the expression.
if (t.match(YIELD, true))
return ReturnOrYield(t, x);
n = new Node(t, { type: ASSIGN });
lhs = ConditionalExpression(t, x);
if (!t.match(ASSIGN)) {
return lhs;
}
n.blockComment = t.lastBlockComment();
switch (lhs.type) {
case OBJECT_INIT:
case ARRAY_INIT:
lhs.destructuredNames = checkDestructuring(t, x, lhs);
// FALL THROUGH
case IDENTIFIER: case DOT: case INDEX: case CALL:
break;
default:
throw t.newSyntaxError("Bad left-hand side of assignment");
break;
}
n.assignOp = lhs.assignOp = t.token.assignOp;
n.push(lhs);
n.push(AssignExpression(t, x));
return n;
}
function ConditionalExpression(t, x) {
var n, n2;
n = OrExpression(t, x);
if (t.match(HOOK)) {
n2 = n;
n = new Node(t, { type: HOOK });
n.push(n2);
/*
* Always accept the 'in' operator in the middle clause of a ternary,
* where it's unambiguous, even if we might be parsing the init of a
* for statement.
*/
n.push(AssignExpression(t, x.update({ inForLoopInit: false })));
if (!t.match(COLON))
throw t.newSyntaxError("missing : after ?");
n.push(AssignExpression(t, x));
}
return n;
}
function OrExpression(t, x) {
var n, n2;
n = AndExpression(t, x);
while (t.match(OR)) {
n2 = new Node(t);
n2.push(n);
n2.push(AndExpression(t, x));
n = n2;
}
return n;
}
function AndExpression(t, x) {
var n, n2;
n = BitwiseOrExpression(t, x);
while (t.match(AND)) {
n2 = new Node(t);
n2.push(n);
n2.push(BitwiseOrExpression(t, x));
n = n2;
}
return n;
}
function BitwiseOrExpression(t, x) {
var n, n2;
n = BitwiseXorExpression(t, x);
while (t.match(BITWISE_OR)) {
n2 = new Node(t);
n2.push(n);
n2.push(BitwiseXorExpression(t, x));
n = n2;
}
return n;
}
function BitwiseXorExpression(t, x) {
var n, n2;
n = BitwiseAndExpression(t, x);
while (t.match(