129 lines
3.8 KiB
JavaScript
129 lines
3.8 KiB
JavaScript
import {types as tt} from "./tokentype"
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import {Parser} from "./state"
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import {lineBreak, skipWhiteSpace} from "./whitespace"
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const pp = Parser.prototype
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// ## Parser utilities
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const literal = /^(?:'((?:[^\']|\.)*)'|"((?:[^\"]|\.)*)"|;)/
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pp.strictDirective = function(start) {
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for (;;) {
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skipWhiteSpace.lastIndex = start
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start += skipWhiteSpace.exec(this.input)[0].length
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let match = literal.exec(this.input.slice(start))
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if (!match) return false
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if ((match[1] || match[2]) == "use strict") return true
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start += match[0].length
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}
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}
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// Predicate that tests whether the next token is of the given
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// type, and if yes, consumes it as a side effect.
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pp.eat = function(type) {
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if (this.type === type) {
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this.next()
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return true
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} else {
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return false
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}
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}
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// Tests whether parsed token is a contextual keyword.
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pp.isContextual = function(name) {
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return this.type === tt.name && this.value === name
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}
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// Consumes contextual keyword if possible.
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pp.eatContextual = function(name) {
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return this.value === name && this.eat(tt.name)
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}
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// Asserts that following token is given contextual keyword.
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pp.expectContextual = function(name) {
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if (!this.eatContextual(name)) this.unexpected()
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}
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// Test whether a semicolon can be inserted at the current position.
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pp.canInsertSemicolon = function() {
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return this.type === tt.eof ||
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this.type === tt.braceR ||
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lineBreak.test(this.input.slice(this.lastTokEnd, this.start))
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}
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pp.insertSemicolon = function() {
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if (this.canInsertSemicolon()) {
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if (this.options.onInsertedSemicolon)
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this.options.onInsertedSemicolon(this.lastTokEnd, this.lastTokEndLoc)
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return true
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}
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}
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// Consume a semicolon, or, failing that, see if we are allowed to
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// pretend that there is a semicolon at this position.
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pp.semicolon = function() {
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if (!this.eat(tt.semi) && !this.insertSemicolon()) this.unexpected()
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}
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pp.afterTrailingComma = function(tokType, notNext) {
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if (this.type == tokType) {
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if (this.options.onTrailingComma)
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this.options.onTrailingComma(this.lastTokStart, this.lastTokStartLoc)
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if (!notNext)
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this.next()
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return true
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}
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}
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// Expect a token of a given type. If found, consume it, otherwise,
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// raise an unexpected token error.
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pp.expect = function(type) {
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this.eat(type) || this.unexpected()
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}
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// Raise an unexpected token error.
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pp.unexpected = function(pos) {
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this.raise(pos != null ? pos : this.start, "Unexpected token")
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}
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export class DestructuringErrors {
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constructor() {
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this.shorthandAssign = this.trailingComma = this.parenthesizedAssign = this.parenthesizedBind = -1
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}
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}
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pp.checkPatternErrors = function(refDestructuringErrors, isAssign) {
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if (!refDestructuringErrors) return
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if (refDestructuringErrors.trailingComma > -1)
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this.raiseRecoverable(refDestructuringErrors.trailingComma, "Comma is not permitted after the rest element")
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let parens = isAssign ? refDestructuringErrors.parenthesizedAssign : refDestructuringErrors.parenthesizedBind
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if (parens > -1) this.raiseRecoverable(parens, "Parenthesized pattern")
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}
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pp.checkExpressionErrors = function(refDestructuringErrors, andThrow) {
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let pos = refDestructuringErrors ? refDestructuringErrors.shorthandAssign : -1
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if (!andThrow) return pos >= 0
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if (pos > -1) this.raise(pos, "Shorthand property assignments are valid only in destructuring patterns")
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}
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pp.checkYieldAwaitInDefaultParams = function() {
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if (this.yieldPos && (!this.awaitPos || this.yieldPos < this.awaitPos))
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this.raise(this.yieldPos, "Yield expression cannot be a default value")
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if (this.awaitPos)
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this.raise(this.awaitPos, "Await expression cannot be a default value")
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}
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pp.isSimpleAssignTarget = function(expr) {
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if (expr.type === "ParenthesizedExpression")
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return this.isSimpleAssignTarget(expr.expression)
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return expr.type === "Identifier" || expr.type === "MemberExpression"
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}
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