89 lines
2.3 KiB
JavaScript
Executable File
89 lines
2.3 KiB
JavaScript
Executable File
import { types as tt } from "./tokentype";
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import { Parser } from "./state";
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import { lineBreak } from "./whitespace";
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const pp = Parser.prototype;
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// ## Parser utilities
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// Test whether a statement node is the string literal `"use strict"`.
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pp.isUseStrict = function (stmt) {
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return stmt.type === "ExpressionStatement" && stmt.expression.type === "Literal" && stmt.expression.raw.slice(1, -1) === "use strict";
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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) {
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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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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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return 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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