diff options
Diffstat (limited to 'node_modules/acorn/src/expression.js')
| -rw-r--r-- | node_modules/acorn/src/expression.js | 830 |
1 files changed, 830 insertions, 0 deletions
diff --git a/node_modules/acorn/src/expression.js b/node_modules/acorn/src/expression.js new file mode 100644 index 000000000..47790d2dc --- /dev/null +++ b/node_modules/acorn/src/expression.js @@ -0,0 +1,830 @@ +// 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 + +import {types as tt} from "./tokentype" +import {Parser} from "./state" +import {DestructuringErrors} from "./parseutil" + +const pp = Parser.prototype + +// Check if property name clashes with already added. +// Object/class getters and setters are not allowed to clash — +// either with each other or with an init property — and in +// strict mode, init properties are also not allowed to be repeated. + +pp.checkPropClash = function(prop, propHash) { + if (this.options.ecmaVersion >= 6 && (prop.computed || prop.method || prop.shorthand)) + return + let {key} = prop, name + switch (key.type) { + case "Identifier": name = key.name; break + case "Literal": name = String(key.value); break + default: return + } + let {kind} = prop + if (this.options.ecmaVersion >= 6) { + if (name === "__proto__" && kind === "init") { + if (propHash.proto) this.raiseRecoverable(key.start, "Redefinition of __proto__ property") + propHash.proto = true + } + return + } + name = "$" + name + let other = propHash[name] + if (other) { + let redefinition + if (kind === "init") { + redefinition = this.strict && other.init || other.get || other.set + } else { + redefinition = other.init || other[kind] + } + if (redefinition) + this.raiseRecoverable(key.start, "Redefinition of property") + } else { + other = propHash[name] = { + init: false, + get: false, + set: false + } + } + other[kind] = true +} + +// ### Expression parsing + +// These nest, from the most general expression type at the top to +// 'atomic', nondivisible expression types at the bottom. Most of +// the functions will simply let the function(s) below them parse, +// and, *if* the syntactic construct they handle is present, wrap +// the AST node that the inner parser gave them in another node. + +// Parse a full expression. The optional arguments are used to +// forbid the `in` operator (in for loops initalization expressions) +// and provide reference for storing '=' operator inside shorthand +// property assignment in contexts where both object expression +// and object pattern might appear (so it's possible to raise +// delayed syntax error at correct position). + +pp.parseExpression = function(noIn, refDestructuringErrors) { + let startPos = this.start, startLoc = this.startLoc + let expr = this.parseMaybeAssign(noIn, refDestructuringErrors) + if (this.type === tt.comma) { + let node = this.startNodeAt(startPos, startLoc) + node.expressions = [expr] + while (this.eat(tt.comma)) node.expressions.push(this.parseMaybeAssign(noIn, refDestructuringErrors)) + return this.finishNode(node, "SequenceExpression") + } + return expr +} + +// Parse an assignment expression. This includes applications of +// operators like `+=`. + +pp.parseMaybeAssign = function(noIn, refDestructuringErrors, afterLeftParse) { + if (this.inGenerator && this.isContextual("yield")) return this.parseYield() + + let ownDestructuringErrors = false, oldParenAssign = -1, oldTrailingComma = -1 + if (refDestructuringErrors) { + oldParenAssign = refDestructuringErrors.parenthesizedAssign + oldTrailingComma = refDestructuringErrors.trailingComma + refDestructuringErrors.parenthesizedAssign = refDestructuringErrors.trailingComma = -1 + } else { + refDestructuringErrors = new DestructuringErrors + ownDestructuringErrors = true + } + + let startPos = this.start, startLoc = this.startLoc + if (this.type == tt.parenL || this.type == tt.name) + this.potentialArrowAt = this.start + let left = this.parseMaybeConditional(noIn, refDestructuringErrors) + if (afterLeftParse) left = afterLeftParse.call(this, left, startPos, startLoc) + if (this.type.isAssign) { + this.checkPatternErrors(refDestructuringErrors, true) + if (!ownDestructuringErrors) DestructuringErrors.call(refDestructuringErrors) + let node = this.startNodeAt(startPos, startLoc) + node.operator = this.value + node.left = this.type === tt.eq ? this.toAssignable(left) : left + refDestructuringErrors.shorthandAssign = -1 // reset because shorthand default was used correctly + this.checkLVal(left) + this.next() + node.right = this.parseMaybeAssign(noIn) + return this.finishNode(node, "AssignmentExpression") + } else { + if (ownDestructuringErrors) this.checkExpressionErrors(refDestructuringErrors, true) + } + if (oldParenAssign > -1) refDestructuringErrors.parenthesizedAssign = oldParenAssign + if (oldTrailingComma > -1) refDestructuringErrors.trailingComma = oldTrailingComma + return left +} + +// Parse a ternary conditional (`?:`) operator. + +pp.parseMaybeConditional = function(noIn, refDestructuringErrors) { + let startPos = this.start, startLoc = this.startLoc + let expr = this.parseExprOps(noIn, refDestructuringErrors) + if (this.checkExpressionErrors(refDestructuringErrors)) return expr + if (this.eat(tt.question)) { + let node = this.startNodeAt(startPos, startLoc) + node.test = expr + node.consequent = this.parseMaybeAssign() + this.expect(tt.colon) + node.alternate = this.parseMaybeAssign(noIn) + return this.finishNode(node, "ConditionalExpression") + } + return expr +} + +// Start the precedence parser. + +pp.parseExprOps = function(noIn, refDestructuringErrors) { + let startPos = this.start, startLoc = this.startLoc + let expr = this.parseMaybeUnary(refDestructuringErrors, false) + if (this.checkExpressionErrors(refDestructuringErrors)) return expr + return expr.start == startPos && expr.type === "ArrowFunctionExpression" ? expr : this.parseExprOp(expr, startPos, startLoc, -1, noIn) +} + +// Parse binary operators with the operator precedence parsing +// algorithm. `left` is the left-hand side of the operator. +// `minPrec` provides context that allows the function to stop and +// defer further parser to one of its callers when it encounters an +// operator that has a lower precedence than the set it is parsing. + +pp.parseExprOp = function(left, leftStartPos, leftStartLoc, minPrec, noIn) { + let prec = this.type.binop + if (prec != null && (!noIn || this.type !== tt._in)) { + if (prec > minPrec) { + let logical = this.type === tt.logicalOR || this.type === tt.logicalAND + let op = this.value + this.next() + let startPos = this.start, startLoc = this.startLoc + let right = this.parseExprOp(this.parseMaybeUnary(null, false), startPos, startLoc, prec, noIn) + let node = this.buildBinary(leftStartPos, leftStartLoc, left, right, op, logical) + return this.parseExprOp(node, leftStartPos, leftStartLoc, minPrec, noIn) + } + } + return left +} + +pp.buildBinary = function(startPos, startLoc, left, right, op, logical) { + let node = this.startNodeAt(startPos, startLoc) + node.left = left + node.operator = op + node.right = right + return this.finishNode(node, logical ? "LogicalExpression" : "BinaryExpression") +} + +// Parse unary operators, both prefix and postfix. + +pp.parseMaybeUnary = function(refDestructuringErrors, sawUnary) { + let startPos = this.start, startLoc = this.startLoc, expr + if (this.inAsync && this.isContextual("await")) { + expr = this.parseAwait(refDestructuringErrors) + sawUnary = true + } else if (this.type.prefix) { + let node = this.startNode(), update = this.type === tt.incDec + node.operator = this.value + node.prefix = true + this.next() + node.argument = this.parseMaybeUnary(null, true) + this.checkExpressionErrors(refDestructuringErrors, true) + if (update) this.checkLVal(node.argument) + else if (this.strict && node.operator === "delete" && + node.argument.type === "Identifier") + this.raiseRecoverable(node.start, "Deleting local variable in strict mode") + else sawUnary = true + expr = this.finishNode(node, update ? "UpdateExpression" : "UnaryExpression") + } else { + expr = this.parseExprSubscripts(refDestructuringErrors) + if (this.checkExpressionErrors(refDestructuringErrors)) return expr + while (this.type.postfix && !this.canInsertSemicolon()) { + let node = this.startNodeAt(startPos, startLoc) + node.operator = this.value + node.prefix = false + node.argument = expr + this.checkLVal(expr) + this.next() + expr = this.finishNode(node, "UpdateExpression") + } + } + + if (!sawUnary && this.eat(tt.starstar)) + return this.buildBinary(startPos, startLoc, expr, this.parseMaybeUnary(null, false), "**", false) + else + return expr +} + +// Parse call, dot, and `[]`-subscript expressions. + +pp.parseExprSubscripts = function(refDestructuringErrors) { + let startPos = this.start, startLoc = this.startLoc + let expr = this.parseExprAtom(refDestructuringErrors) + let skipArrowSubscripts = expr.type === "ArrowFunctionExpression" && this.input.slice(this.lastTokStart, this.lastTokEnd) !== ")" + if (this.checkExpressionErrors(refDestructuringErrors) || skipArrowSubscripts) return expr + let result = this.parseSubscripts(expr, startPos, startLoc) + if (refDestructuringErrors && result.type === "MemberExpression") { + if (refDestructuringErrors.parenthesizedAssign >= result.start) refDestructuringErrors.parenthesizedAssign = -1 + if (refDestructuringErrors.parenthesizedBind >= result.start) refDestructuringErrors.parenthesizedBind = -1 + } + return result +} + +pp.parseSubscripts = function(base, startPos, startLoc, noCalls) { + let maybeAsyncArrow = this.options.ecmaVersion >= 8 && base.type === "Identifier" && base.name === "async" && + this.lastTokEnd == base.end && !this.canInsertSemicolon() + for (let computed;;) { + if ((computed = this.eat(tt.bracketL)) || this.eat(tt.dot)) { + let node = this.startNodeAt(startPos, startLoc) + node.object = base + node.property = computed ? this.parseExpression() : this.parseIdent(true) + node.computed = !!computed + if (computed) this.expect(tt.bracketR) + base = this.finishNode(node, "MemberExpression") + } else if (!noCalls && this.eat(tt.parenL)) { + let refDestructuringErrors = new DestructuringErrors, oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos + this.yieldPos = 0 + this.awaitPos = 0 + let exprList = this.parseExprList(tt.parenR, this.options.ecmaVersion >= 8, false, refDestructuringErrors) + if (maybeAsyncArrow && !this.canInsertSemicolon() && this.eat(tt.arrow)) { + this.checkPatternErrors(refDestructuringErrors, false) + this.checkYieldAwaitInDefaultParams() + this.yieldPos = oldYieldPos + this.awaitPos = oldAwaitPos + return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), exprList, true) + } + this.checkExpressionErrors(refDestructuringErrors, true) + this.yieldPos = oldYieldPos || this.yieldPos + this.awaitPos = oldAwaitPos || this.awaitPos + let node = this.startNodeAt(startPos, startLoc) + node.callee = base + node.arguments = exprList + base = this.finishNode(node, "CallExpression") + } else if (this.type === tt.backQuote) { + let node = this.startNodeAt(startPos, startLoc) + node.tag = base + node.quasi = this.parseTemplate() + base = this.finishNode(node, "TaggedTemplateExpression") + } else { + return base + } + } +} + +// Parse an atomic expression — either a single token that is an +// expression, an expression started by a keyword like `function` or +// `new`, or an expression wrapped in punctuation like `()`, `[]`, +// or `{}`. + +pp.parseExprAtom = function(refDestructuringErrors) { + let node, canBeArrow = this.potentialArrowAt == this.start + switch (this.type) { + case tt._super: + if (!this.inFunction) + this.raise(this.start, "'super' outside of function or class") + + case tt._this: + let type = this.type === tt._this ? "ThisExpression" : "Super" + node = this.startNode() + this.next() + return this.finishNode(node, type) + + case tt.name: + let startPos = this.start, startLoc = this.startLoc + let id = this.parseIdent(this.type !== tt.name) + if (this.options.ecmaVersion >= 8 && id.name === "async" && !this.canInsertSemicolon() && this.eat(tt._function)) + return this.parseFunction(this.startNodeAt(startPos, startLoc), false, false, true) + if (canBeArrow && !this.canInsertSemicolon()) { + if (this.eat(tt.arrow)) + return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), [id], false) + if (this.options.ecmaVersion >= 8 && id.name === "async" && this.type === tt.name) { + id = this.parseIdent() + if (this.canInsertSemicolon() || !this.eat(tt.arrow)) + this.unexpected() + return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), [id], true) + } + } + return id + + case tt.regexp: + let value = this.value + node = this.parseLiteral(value.value) + node.regex = {pattern: value.pattern, flags: value.flags} + return node + + case tt.num: case tt.string: + return this.parseLiteral(this.value) + + case tt._null: case tt._true: case tt._false: + node = this.startNode() + node.value = this.type === tt._null ? null : this.type === tt._true + node.raw = this.type.keyword + this.next() + return this.finishNode(node, "Literal") + + case tt.parenL: + let start = this.start, expr = this.parseParenAndDistinguishExpression(canBeArrow) + if (refDestructuringErrors) { + if (refDestructuringErrors.parenthesizedAssign < 0 && !this.isSimpleAssignTarget(expr)) + refDestructuringErrors.parenthesizedAssign = start + if (refDestructuringErrors.parenthesizedBind < 0) + refDestructuringErrors.parenthesizedBind = start + } + return expr + + case tt.bracketL: + node = this.startNode() + this.next() + node.elements = this.parseExprList(tt.bracketR, true, true, refDestructuringErrors) + return this.finishNode(node, "ArrayExpression") + + case tt.braceL: + return this.parseObj(false, refDestructuringErrors) + + case tt._function: + node = this.startNode() + this.next() + return this.parseFunction(node, false) + + case tt._class: + return this.parseClass(this.startNode(), false) + + case tt._new: + return this.parseNew() + + case tt.backQuote: + return this.parseTemplate() + + default: + this.unexpected() + } +} + +pp.parseLiteral = function(value) { + let node = this.startNode() + node.value = value + node.raw = this.input.slice(this.start, this.end) + this.next() + return this.finishNode(node, "Literal") +} + +pp.parseParenExpression = function() { + this.expect(tt.parenL) + let val = this.parseExpression() + this.expect(tt.parenR) + return val +} + +pp.parseParenAndDistinguishExpression = function(canBeArrow) { + let startPos = this.start, startLoc = this.startLoc, val, allowTrailingComma = this.options.ecmaVersion >= 8 + if (this.options.ecmaVersion >= 6) { + this.next() + + let innerStartPos = this.start, innerStartLoc = this.startLoc + let exprList = [], first = true, lastIsComma = false + let refDestructuringErrors = new DestructuringErrors, oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, spreadStart, innerParenStart + this.yieldPos = 0 + this.awaitPos = 0 + while (this.type !== tt.parenR) { + first ? first = false : this.expect(tt.comma) + if (allowTrailingComma && this.afterTrailingComma(tt.parenR, true)) { + lastIsComma = true + break + } else if (this.type === tt.ellipsis) { + spreadStart = this.start + exprList.push(this.parseParenItem(this.parseRest())) + if (this.type === tt.comma) this.raise(this.start, "Comma is not permitted after the rest element") + break + } else { + if (this.type === tt.parenL && !innerParenStart) { + innerParenStart = this.start + } + exprList.push(this.parseMaybeAssign(false, refDestructuringErrors, this.parseParenItem)) + } + } + let innerEndPos = this.start, innerEndLoc = this.startLoc + this.expect(tt.parenR) + + if (canBeArrow && !this.canInsertSemicolon() && this.eat(tt.arrow)) { + this.checkPatternErrors(refDestructuringErrors, false) + this.checkYieldAwaitInDefaultParams() + if (innerParenStart) this.unexpected(innerParenStart) + this.yieldPos = oldYieldPos + this.awaitPos = oldAwaitPos + return this.parseParenArrowList(startPos, startLoc, exprList) + } + + if (!exprList.length || lastIsComma) this.unexpected(this.lastTokStart) + if (spreadStart) this.unexpected(spreadStart) + this.checkExpressionErrors(refDestructuringErrors, true) + this.yieldPos = oldYieldPos || this.yieldPos + this.awaitPos = oldAwaitPos || this.awaitPos + + if (exprList.length > 1) { + val = this.startNodeAt(innerStartPos, innerStartLoc) + val.expressions = exprList + this.finishNodeAt(val, "SequenceExpression", innerEndPos, innerEndLoc) + } else { + val = exprList[0] + } + } else { + val = this.parseParenExpression() + } + + if (this.options.preserveParens) { + let par = this.startNodeAt(startPos, startLoc) + par.expression = val + return this.finishNode(par, "ParenthesizedExpression") + } else { + return val + } +} + +pp.parseParenItem = function(item) { + return item +} + +pp.parseParenArrowList = function(startPos, startLoc, exprList) { + return this.parseArrowExpression(this.startNodeAt(startPos, startLoc), exprList) +} + +// New's precedence is slightly tricky. It must allow its argument to +// be a `[]` or dot subscript expression, but not a call — at least, +// not without wrapping it in parentheses. Thus, it uses the noCalls +// argument to parseSubscripts to prevent it from consuming the +// argument list. + +const empty = [] + +pp.parseNew = function() { + let node = this.startNode() + let meta = this.parseIdent(true) + if (this.options.ecmaVersion >= 6 && this.eat(tt.dot)) { + node.meta = meta + node.property = this.parseIdent(true) + if (node.property.name !== "target") + this.raiseRecoverable(node.property.start, "The only valid meta property for new is new.target") + if (!this.inFunction) + this.raiseRecoverable(node.start, "new.target can only be used in functions") + return this.finishNode(node, "MetaProperty") + } + let startPos = this.start, startLoc = this.startLoc + node.callee = this.parseSubscripts(this.parseExprAtom(), startPos, startLoc, true) + if (this.eat(tt.parenL)) node.arguments = this.parseExprList(tt.parenR, this.options.ecmaVersion >= 8, false) + else node.arguments = empty + return this.finishNode(node, "NewExpression") +} + +// Parse template expression. + +pp.parseTemplateElement = function() { + let elem = this.startNode() + elem.value = { + raw: this.input.slice(this.start, this.end).replace(/\r\n?/g, "\n"), + cooked: this.value + } + this.next() + elem.tail = this.type === tt.backQuote + return this.finishNode(elem, "TemplateElement") +} + +pp.parseTemplate = function() { + let node = this.startNode() + this.next() + node.expressions = [] + let curElt = this.parseTemplateElement() + node.quasis = [curElt] + while (!curElt.tail) { + this.expect(tt.dollarBraceL) + node.expressions.push(this.parseExpression()) + this.expect(tt.braceR) + node.quasis.push(curElt = this.parseTemplateElement()) + } + this.next() + return this.finishNode(node, "TemplateLiteral") +} + +// Parse an object literal or binding pattern. + +pp.parseObj = function(isPattern, refDestructuringErrors) { + let node = this.startNode(), first = true, propHash = {} + node.properties = [] + this.next() + while (!this.eat(tt.braceR)) { + if (!first) { + this.expect(tt.comma) + if (this.afterTrailingComma(tt.braceR)) break + } else first = false + + let prop = this.startNode(), isGenerator, isAsync, startPos, startLoc + if (this.options.ecmaVersion >= 6) { + prop.method = false + prop.shorthand = false + if (isPattern || refDestructuringErrors) { + startPos = this.start + startLoc = this.startLoc + } + if (!isPattern) + isGenerator = this.eat(tt.star) + } + this.parsePropertyName(prop) + if (!isPattern && this.options.ecmaVersion >= 8 && !isGenerator && !prop.computed && + prop.key.type === "Identifier" && prop.key.name === "async" && this.type !== tt.parenL && + this.type !== tt.colon && !this.canInsertSemicolon()) { + isAsync = true + this.parsePropertyName(prop, refDestructuringErrors) + } else { + isAsync = false + } + this.parsePropertyValue(prop, isPattern, isGenerator, isAsync, startPos, startLoc, refDestructuringErrors) + this.checkPropClash(prop, propHash) + node.properties.push(this.finishNode(prop, "Property")) + } + return this.finishNode(node, isPattern ? "ObjectPattern" : "ObjectExpression") +} + +pp.parsePropertyValue = function(prop, isPattern, isGenerator, isAsync, startPos, startLoc, refDestructuringErrors) { + if ((isGenerator || isAsync) && this.type === tt.colon) + this.unexpected() + + if (this.eat(tt.colon)) { + prop.value = isPattern ? this.parseMaybeDefault(this.start, this.startLoc) : this.parseMaybeAssign(false, refDestructuringErrors) + prop.kind = "init" + } else if (this.options.ecmaVersion >= 6 && this.type === tt.parenL) { + if (isPattern) this.unexpected() + prop.kind = "init" + prop.method = true + prop.value = this.parseMethod(isGenerator, isAsync) + } else if (this.options.ecmaVersion >= 5 && !prop.computed && prop.key.type === "Identifier" && + (prop.key.name === "get" || prop.key.name === "set") && + (this.type != tt.comma && this.type != tt.braceR)) { + if (isGenerator || isAsync || isPattern) this.unexpected() + prop.kind = prop.key.name + this.parsePropertyName(prop) + prop.value = this.parseMethod(false) + let paramCount = prop.kind === "get" ? 0 : 1 + if (prop.value.params.length !== paramCount) { + let start = prop.value.start + if (prop.kind === "get") + this.raiseRecoverable(start, "getter should have no params") + else + this.raiseRecoverable(start, "setter should have exactly one param") + } else { + if (prop.kind === "set" && prop.value.params[0].type === "RestElement") + this.raiseRecoverable(prop.value.params[0].start, "Setter cannot use rest params") + } + } else if (this.options.ecmaVersion >= 6 && !prop.computed && prop.key.type === "Identifier") { + if (this.keywords.test(prop.key.name) || + (this.strict ? this.reservedWordsStrict : this.reservedWords).test(prop.key.name) || + (this.inGenerator && prop.key.name == "yield") || + (this.inAsync && prop.key.name == "await")) + this.raiseRecoverable(prop.key.start, "'" + prop.key.name + "' can not be used as shorthand property") + prop.kind = "init" + if (isPattern) { + prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key) + } else if (this.type === tt.eq && refDestructuringErrors) { + if (refDestructuringErrors.shorthandAssign < 0) + refDestructuringErrors.shorthandAssign = this.start + prop.value = this.parseMaybeDefault(startPos, startLoc, prop.key) + } else { + prop.value = prop.key + } + prop.shorthand = true + } else this.unexpected() +} + +pp.parsePropertyName = function(prop) { + if (this.options.ecmaVersion >= 6) { + if (this.eat(tt.bracketL)) { + prop.computed = true + prop.key = this.parseMaybeAssign() + this.expect(tt.bracketR) + return prop.key + } else { + prop.computed = false + } + } + return prop.key = this.type === tt.num || this.type === tt.string ? this.parseExprAtom() : this.parseIdent(true) +} + +// Initialize empty function node. + +pp.initFunction = function(node) { + node.id = null + if (this.options.ecmaVersion >= 6) { + node.generator = false + node.expression = false + } + if (this.options.ecmaVersion >= 8) + node.async = false +} + +// Parse object or class method. + +pp.parseMethod = function(isGenerator, isAsync) { + let node = this.startNode(), oldInGen = this.inGenerator, oldInAsync = this.inAsync, + oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, oldInFunc = this.inFunction + + this.initFunction(node) + if (this.options.ecmaVersion >= 6) + node.generator = isGenerator + if (this.options.ecmaVersion >= 8) + node.async = !!isAsync + + this.inGenerator = node.generator + this.inAsync = node.async + this.yieldPos = 0 + this.awaitPos = 0 + this.inFunction = true + this.enterFunctionScope() + + this.expect(tt.parenL) + node.params = this.parseBindingList(tt.parenR, false, this.options.ecmaVersion >= 8) + this.checkYieldAwaitInDefaultParams() + this.parseFunctionBody(node, false) + + this.inGenerator = oldInGen + this.inAsync = oldInAsync + this.yieldPos = oldYieldPos + this.awaitPos = oldAwaitPos + this.inFunction = oldInFunc + return this.finishNode(node, "FunctionExpression") +} + +// Parse arrow function expression with given parameters. + +pp.parseArrowExpression = function(node, params, isAsync) { + let oldInGen = this.inGenerator, oldInAsync = this.inAsync, + oldYieldPos = this.yieldPos, oldAwaitPos = this.awaitPos, oldInFunc = this.inFunction + + this.enterFunctionScope() + this.initFunction(node) + if (this.options.ecmaVersion >= 8) + node.async = !!isAsync + + this.inGenerator = false + this.inAsync = node.async + this.yieldPos = 0 + this.awaitPos = 0 + this.inFunction = true + + node.params = this.toAssignableList(params, true) + this.parseFunctionBody(node, true) + + this.inGenerator = oldInGen + this.inAsync = oldInAsync + this.yieldPos = oldYieldPos + this.awaitPos = oldAwaitPos + this.inFunction = oldInFunc + return this.finishNode(node, "ArrowFunctionExpression") +} + +// Parse function body and check parameters. + +pp.parseFunctionBody = function(node, isArrowFunction) { + let isExpression = isArrowFunction && this.type !== tt.braceL + let oldStrict = this.strict, useStrict = false + + if (isExpression) { + node.body = this.parseMaybeAssign() + node.expression = true + this.checkParams(node, false) + } else { + let nonSimple = this.options.ecmaVersion >= 7 && !this.isSimpleParamList(node.params) + if (!oldStrict || nonSimple) { + useStrict = this.strictDirective(this.end) + // If this is a strict mode function, verify that argument names + // are not repeated, and it does not try to bind the words `eval` + // or `arguments`. + if (useStrict && nonSimple) + this.raiseRecoverable(node.start, "Illegal 'use strict' directive in function with non-simple parameter list") + } + // Start a new scope with regard to labels and the `inFunction` + // flag (restore them to their old value afterwards). + let oldLabels = this.labels + this.labels = [] + if (useStrict) this.strict = true + + // Add the params to varDeclaredNames to ensure that an error is thrown + // if a let/const declaration in the function clashes with one of the params. + this.checkParams(node, !oldStrict && !useStrict && !isArrowFunction && this.isSimpleParamList(node.params)) + node.body = this.parseBlock(false) + node.expression = false + this.labels = oldLabels + } + this.exitFunctionScope() + + if (this.strict && node.id) { + // Ensure the function name isn't a forbidden identifier in strict mode, e.g. 'eval' + this.checkLVal(node.id, "none") + } + this.strict = oldStrict +} + +pp.isSimpleParamList = function(params) { + for (let i = 0; i < params.length; i++) + if (params[i].type !== "Identifier") return false + return true +} + +// Checks function params for various disallowed patterns such as using "eval" +// or "arguments" and duplicate parameters. + +pp.checkParams = function(node, allowDuplicates) { + let nameHash = {} + for (let i = 0; i < node.params.length; i++) this.checkLVal(node.params[i], "var", allowDuplicates ? null : nameHash) +} + +// Parses a comma-separated list of expressions, and returns them as +// an array. `close` is the token type that ends the list, and +// `allowEmpty` can be turned on to allow subsequent commas with +// nothing in between them to be parsed as `null` (which is needed +// for array literals). + +pp.parseExprList = function(close, allowTrailingComma, allowEmpty, refDestructuringErrors) { + let elts = [], first = true + while (!this.eat(close)) { + if (!first) { + this.expect(tt.comma) + if (allowTrailingComma && this.afterTrailingComma(close)) break + } else first = false + + let elt + if (allowEmpty && this.type === tt.comma) + elt = null + else if (this.type === tt.ellipsis) { + elt = this.parseSpread(refDestructuringErrors) + if (refDestructuringErrors && this.type === tt.comma && refDestructuringErrors.trailingComma < 0) + refDestructuringErrors.trailingComma = this.start + } else { + elt = this.parseMaybeAssign(false, refDestructuringErrors) + } + elts.push(elt) + } + return elts +} + +// Parse the next token as an identifier. If `liberal` is true (used +// when parsing properties), it will also convert keywords into +// identifiers. + +pp.parseIdent = function(liberal) { + let node = this.startNode() + if (liberal && this.options.allowReserved == "never") liberal = false + if (this.type === tt.name) { + if (!liberal && (this.strict ? this.reservedWordsStrict : this.reservedWords).test(this.value) && + (this.options.ecmaVersion >= 6 || + this.input.slice(this.start, this.end).indexOf("\\") == -1)) + this.raiseRecoverable(this.start, "The keyword '" + this.value + "' is reserved") + if (this.inGenerator && this.value === "yield") + this.raiseRecoverable(this.start, "Can not use 'yield' as identifier inside a generator") + if (this.inAsync && this.value === "await") + this.raiseRecoverable(this.start, "Can not use 'await' as identifier inside an async function") + node.name = this.value + } else if (liberal && this.type.keyword) { + node.name = this.type.keyword + } else { + this.unexpected() + } + this.next() + return this.finishNode(node, "Identifier") +} + +// Parses yield expression inside generator. + +pp.parseYield = function() { + if (!this.yieldPos) this.yieldPos = this.start + + let node = this.startNode() + this.next() + if (this.type == tt.semi || this.canInsertSemicolon() || (this.type != tt.star && !this.type.startsExpr)) { + node.delegate = false + node.argument = null + } else { + node.delegate = this.eat(tt.star) + node.argument = this.parseMaybeAssign() + } + return this.finishNode(node, "YieldExpression") +} + +pp.parseAwait = function() { + if (!this.awaitPos) this.awaitPos = this.start + + let node = this.startNode() + this.next() + node.argument = this.parseMaybeUnary(null, true) + return this.finishNode(node, "AwaitExpression") +} |