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Make let a contextual keyword

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This commit is contained in:
Daniel Tschinder 2019-01-21 19:46:40 -08:00
parent 65febdd13a
commit 178f2d7949
24 changed files with 636 additions and 42 deletions
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77
packages/babel-parser/src/parser/statement.js
View File

@ -3,8 +3,13 @@
import * as N from "../types";
import { types as tt, type TokenType } from "../tokenizer/types";
import ExpressionParser from "./expression";
import { isIdentifierChar } from "../util/identifier";
import {
isIdentifierChar,
isIdentifierStart,
keywordRelationalOperator,
} from "../util/identifier";
import { lineBreak, skipWhiteSpace } from "../util/whitespace";
import * as charCodes from "charcodes";
// Reused empty array added for node fields that are always empty.
@ -71,6 +76,33 @@ export default class StatementParser extends ExpressionParser {
return this.finishNode(node, "InterpreterDirective");
}
isLet() {
if (!this.isContextual("let")) {
return false;
}
skipWhiteSpace.lastIndex = this.state.pos;
const skip = skipWhiteSpace.exec(this.state.input);
// $FlowIgnore
const next = this.state.pos + skip[0].length;
const nextCh = this.state.input.charCodeAt(next);
if (
(nextCh === charCodes.leftCurlyBrace &&
!lineBreak.test(this.state.input.slice(this.state.end, next))) ||
nextCh === charCodes.leftSquareBracket
) {
return true;
}
if (isIdentifierStart(nextCh)) {
let pos = next + 1;
while (isIdentifierChar(this.state.input.charCodeAt(pos))) {
++pos;
}
const ident = this.state.input.slice(next, pos);
if (!keywordRelationalOperator.test(ident)) return true;
}
return false;
}
// Parse a single statement.
//
// If expecting a statement and finding a slash operator, parse a
@ -86,8 +118,14 @@ export default class StatementParser extends ExpressionParser {
}
parseStatementContent(declaration: boolean, topLevel: ?boolean): N.Statement {
const starttype = this.state.type;
let starttype = this.state.type;
const node = this.startNode();
let kind;
if (this.isLet()) {
starttype = tt._var;
kind = "let";
}
// Most types of statements are recognized by the keyword they
// start with. Many are trivial to parse, some require a bit of
@ -129,12 +167,11 @@ export default class StatementParser extends ExpressionParser {
case tt._try:
return this.parseTryStatement(node);
case tt._let:
case tt._const:
if (!declaration) this.unexpected(); // NOTE: falls through to _var
case tt._var:
return this.parseVarStatement(node, starttype);
kind = kind || this.state.value;
if (!declaration && kind !== "var") this.unexpected();
return this.parseVarStatement(node, kind);
case tt._while:
return this.parseWhileStatement(node);
@ -424,18 +461,19 @@ export default class StatementParser extends ExpressionParser {
return this.parseFor(node, null);
}
if (this.match(tt._var) || this.match(tt._let) || this.match(tt._const)) {
const isLet = this.isLet();
if (this.match(tt._var) || this.match(tt._const) || isLet) {
const init = this.startNode();
const varKind = this.state.type;
const kind = isLet ? "let" : this.state.value;
this.next();
this.parseVar(init, true, varKind);
this.parseVar(init, true, kind);
this.finishNode(init, "VariableDeclaration");
if (this.match(tt._in) || this.isContextual("of")) {
if (init.declarations.length === 1) {
const declaration = init.declarations[0];
const isForInInitializer =
varKind === tt._var &&
kind === "var" &&
declaration.init &&
declaration.id.type != "ObjectPattern" &&
declaration.id.type != "ArrayPattern" &&
@ -606,7 +644,7 @@ export default class StatementParser extends ExpressionParser {
parseVarStatement(
node: N.VariableDeclaration,
kind: TokenType,
kind: "var" | "let" | "const",
): N.VariableDeclaration {
this.next();
this.parseVar(node, false, kind);
@ -862,12 +900,11 @@ export default class StatementParser extends ExpressionParser {
parseVar(
node: N.VariableDeclaration,
isFor: boolean,
kind: TokenType,
kind: "var" | "let" | "const",
): N.VariableDeclaration {
const declarations = (node.declarations = []);
const isTypescript = this.hasPlugin("typescript");
// $FlowFixMe
node.kind = kind.keyword;
node.kind = kind;
for (;;) {
const decl = this.startNode();
this.parseVarHead(decl);
@ -875,7 +912,7 @@ export default class StatementParser extends ExpressionParser {
decl.init = this.parseMaybeAssign(isFor);
} else {
if (
kind === tt._const &&
kind === "const" &&
!(this.match(tt._in) || this.isContextual("of"))
) {
// `const` with no initializer is allowed in TypeScript.
@ -1638,11 +1675,7 @@ export default class StatementParser extends ExpressionParser {
}
this.parseDecorators(false);
return this.parseClass(expr, true, true);
} else if (
this.match(tt._let) ||
this.match(tt._const) ||
this.match(tt._var)
) {
} else if (this.match(tt._const) || this.match(tt._var) || this.isLet()) {
return this.raise(
this.state.start,
"Only expressions, functions or classes are allowed as the `default` export.",
@ -1661,7 +1694,7 @@ export default class StatementParser extends ExpressionParser {
isExportDefaultSpecifier(): boolean {
if (this.match(tt.name)) {
return this.state.value !== "async";
return this.state.value !== "async" && this.state.value !== "let";
}
if (!this.match(tt._default)) {
@ -1710,9 +1743,9 @@ export default class StatementParser extends ExpressionParser {
return (
this.state.type.keyword === "var" ||
this.state.type.keyword === "const" ||
this.state.type.keyword === "let" ||
this.state.type.keyword === "function" ||
this.state.type.keyword === "class" ||
this.isLet() ||
this.isAsyncFunction()
);
}

2
packages/babel-parser/src/plugins/flow.js
View File

@ -344,7 +344,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
} else {
if (
this.match(tt._const) ||
this.match(tt._let) ||
this.isLet() ||
((this.isContextual("type") || this.isContextual("interface")) &&
!insideModule)
) {

13
packages/babel-parser/src/plugins/typescript.js
View File

@ -1190,8 +1190,15 @@ export default (superClass: Class<Parser>): Class<Parser> =>
if (this.isLineTerminator()) {
return;
}
let starttype = this.state.type;
let kind;
switch (this.state.type) {
if (this.isContextual("let")) {
starttype = tt._var;
kind = "let";
}
switch (starttype) {
case tt._function:
this.next();
return this.parseFunction(nany, /* isStatement */ true);
@ -1210,8 +1217,8 @@ export default (superClass: Class<Parser>): Class<Parser> =>
}
// falls through
case tt._var:
case tt._let:
return this.parseVarStatement(nany, this.state.type);
kind = kind || this.state.value;
return this.parseVarStatement(nany, kind);
case tt.name: {
const value = this.state.value;
if (value === "global") {

4
packages/babel-parser/src/tokenizer/index.js
View File

@ -1384,8 +1384,8 @@ export default class Tokenizer extends LocationParser {
if (
prevType === tt._var ||
prevType === tt._let ||
prevType === tt._const
prevType === tt._const ||
prevType === tt.name
) {
return false;
}

1
packages/babel-parser/src/tokenizer/types.js
View File

@ -180,7 +180,6 @@ export const keywords = Object.create(null, {
throw: makeKeywordProps("throw", { beforeExpr, prefix, startsExpr }),
try: makeKeywordProps("try"),
var: makeKeywordProps("var"),
let: makeKeywordProps("let"),
const: makeKeywordProps("const"),
while: makeKeywordProps("while", { isLoop }),
with: makeKeywordProps("with"),

3
packages/babel-parser/src/util/identifier.js
View File

@ -57,7 +57,6 @@ const keywords = new Set([
"new",
"in",
"this",
"let",
"const",
"class",
"extends",
@ -71,6 +70,8 @@ export function isKeyword(word: string): boolean {
return keywords.has(word);
}
export const keywordRelationalOperator = /^in(stanceof)?$/;
// ## Character categories
// Big ugly regular expressions that matches characters in the

1
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-1/input.js vendored Normal file
View File

@ -0,0 +1 @@
let + 1

103
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-1/output.json vendored Normal file
View File

@ -0,0 +1,103 @@
{
"type": "File",
"start": 0,
"end": 7,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 7
}
},
"program": {
"type": "Program",
"start": 0,
"end": 7,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 7
}
},
"sourceType": "script",
"interpreter": null,
"body": [
{
"type": "ExpressionStatement",
"start": 0,
"end": 7,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 7
}
},
"expression": {
"type": "BinaryExpression",
"start": 0,
"end": 7,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 7
}
},
"left": {
"type": "Identifier",
"start": 0,
"end": 3,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 3
},
"identifierName": "let"
},
"name": "let"
},
"operator": "+",
"right": {
"type": "NumericLiteral",
"start": 6,
"end": 7,
"loc": {
"start": {
"line": 1,
"column": 6
},
"end": {
"line": 1,
"column": 7
}
},
"extra": {
"rawValue": 1,
"raw": "1"
},
"value": 1
}
}
}
],
"directives": []
}
}

1
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-2/input.js vendored Normal file
View File

@ -0,0 +1 @@
var let = 1

105
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-2/output.json vendored Normal file
View File

@ -0,0 +1,105 @@
{
"type": "File",
"start": 0,
"end": 11,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 11
}
},
"program": {
"type": "Program",
"start": 0,
"end": 11,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 11
}
},
"sourceType": "script",
"interpreter": null,
"body": [
{
"type": "VariableDeclaration",
"start": 0,
"end": 11,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 11
}
},
"declarations": [
{
"type": "VariableDeclarator",
"start": 4,
"end": 11,
"loc": {
"start": {
"line": 1,
"column": 4
},
"end": {
"line": 1,
"column": 11
}
},
"id": {
"type": "Identifier",
"start": 4,
"end": 7,
"loc": {
"start": {
"line": 1,
"column": 4
},
"end": {
"line": 1,
"column": 7
},
"identifierName": "let"
},
"name": "let"
},
"init": {
"type": "NumericLiteral",
"start": 10,
"end": 11,
"loc": {
"start": {
"line": 1,
"column": 10
},
"end": {
"line": 1,
"column": 11
}
},
"extra": {
"rawValue": 1,
"raw": "1"
},
"value": 1
}
}
],
"kind": "var"
}
],
"directives": []
}
}

1
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-3/input.js vendored Normal file
View File

@ -0,0 +1 @@
let instanceof Foo

100
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-3/output.json vendored Normal file
View File

@ -0,0 +1,100 @@
{
"type": "File",
"start": 0,
"end": 18,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 18
}
},
"program": {
"type": "Program",
"start": 0,
"end": 18,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 18
}
},
"sourceType": "script",
"interpreter": null,
"body": [
{
"type": "ExpressionStatement",
"start": 0,
"end": 18,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 18
}
},
"expression": {
"type": "BinaryExpression",
"start": 0,
"end": 18,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 18
}
},
"left": {
"type": "Identifier",
"start": 0,
"end": 3,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 3
},
"identifierName": "let"
},
"name": "let"
},
"operator": "instanceof",
"right": {
"type": "Identifier",
"start": 15,
"end": 18,
"loc": {
"start": {
"line": 1,
"column": 15
},
"end": {
"line": 1,
"column": 18
},
"identifierName": "Foo"
},
"name": "Foo"
}
}
}
],
"directives": []
}
}

1
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-4/input.js vendored Normal file
View File

@ -0,0 +1 @@
let in {}

99
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-4/output.json vendored Normal file
View File

@ -0,0 +1,99 @@
{
"type": "File",
"start": 0,
"end": 9,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 9
}
},
"program": {
"type": "Program",
"start": 0,
"end": 9,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 9
}
},
"sourceType": "script",
"interpreter": null,
"body": [
{
"type": "ExpressionStatement",
"start": 0,
"end": 9,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 9
}
},
"expression": {
"type": "BinaryExpression",
"start": 0,
"end": 9,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 9
}
},
"left": {
"type": "Identifier",
"start": 0,
"end": 3,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 3
},
"identifierName": "let"
},
"name": "let"
},
"operator": "in",
"right": {
"type": "ObjectExpression",
"start": 7,
"end": 9,
"loc": {
"start": {
"line": 1,
"column": 7
},
"end": {
"line": 1,
"column": 9
}
},
"properties": []
}
}
}
],
"directives": []
}
}

2
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-5/input.js vendored Normal file
View File

@ -0,0 +1,2 @@
if (1) let
{}

120
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-5/output.json vendored Normal file
View File

@ -0,0 +1,120 @@
{
"type": "File",
"start": 0,
"end": 13,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 2,
"column": 2
}
},
"program": {
"type": "Program",
"start": 0,
"end": 13,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 2,
"column": 2
}
},
"sourceType": "script",
"interpreter": null,
"body": [
{
"type": "IfStatement",
"start": 0,
"end": 10,
"loc": {
"start": {
"line": 1,
"column": 0
},
"end": {
"line": 1,
"column": 10
}
},
"test": {
"type": "NumericLiteral",
"start": 4,
"end": 5,
"loc": {
"start": {
"line": 1,
"column": 4
},
"end": {
"line": 1,
"column": 5
}
},
"extra": {
"rawValue": 1,
"raw": "1"
},
"value": 1
},
"consequent": {
"type": "ExpressionStatement",
"start": 7,
"end": 10,
"loc": {
"start": {
"line": 1,
"column": 7
},
"end": {
"line": 1,
"column": 10
}
},
"expression": {
"type": "Identifier",
"start": 7,
"end": 10,
"loc": {
"start": {
"line": 1,
"column": 7
},
"end": {
"line": 1,
"column": 10
},
"identifierName": "let"
},
"name": "let"
}
},
"alternate": null
},
{
"type": "BlockStatement",
"start": 11,
"end": 13,
"loc": {
"start": {
"line": 2,
"column": 0
},
"end": {
"line": 2,
"column": 2
}
},
"body": [],
"directives": []
}
],
"directives": []
}
}

2
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-strict-fail/input.js vendored Normal file
View File

@ -0,0 +1,2 @@
"use strict";
let + 1

3
packages/babel-parser/test/fixtures/es2015/let/let-as-identifier-strict-fail/options.json vendored Normal file
View File

@ -0,0 +1,3 @@
{
"throws": "let is a reserved word in strict mode (2:0)"
}

2
packages/babel-parser/test/fixtures/esprima/invalid-syntax/migrated_0232/options.json vendored
View File

@ -1,3 +1,3 @@
{
"throws": "Unexpected token (1:37)"
"throws": "let is a reserved word in strict mode (1:37)"
}

1
packages/babel-parser/test/fixtures/esprima/invalid-syntax/migrated_0238/input.js vendored
View File

@ -1 +0,0 @@
var let

3
packages/babel-parser/test/fixtures/esprima/invalid-syntax/migrated_0238/options.json vendored
View File

@ -1,3 +0,0 @@
{
"throws": "Unexpected token (1:4)"
}

1
packages/babel-parser/test/fixtures/esprima/invalid-syntax/migrated_0253/input.js vendored
View File

@ -1 +0,0 @@
let

3
packages/babel-parser/test/fixtures/esprima/invalid-syntax/migrated_0253/options.json vendored
View File

@ -1,3 +0,0 @@
{
"throws": "Unexpected token (1:3)"
}

30
packages/babel-parser/test/unit/util/identifier.js
View File

@ -1,18 +1,42 @@
import { isKeyword } from "../../../src/util/identifier";
import {
isKeyword,
keywordRelationalOperator,
} from "../../../src/util/identifier";
describe("identifier", () => {
describe("isKeyword", () => {
it("break is a keyword", () => {
expect(isKeyword("break")).toBe(true);
});
it("let is a keyword", () => {
expect(isKeyword("let")).toBe(true);
it("const is a keyword", () => {
expect(isKeyword("const")).toBe(true);
});
it("super is a keyword", () => {
expect(isKeyword("super")).toBe(true);
});
it("let is not a keyword", () => {
expect(isKeyword("let")).toBe(false);
});
it("abc is not a keyword", () => {
expect(isKeyword("abc")).toBe(false);
});
});
describe("keywordRelationalOperator", () => {
it("in is true", () => {
expect(keywordRelationalOperator.test("in")).toBe(true);
});
it("instanceof is true", () => {
expect(keywordRelationalOperator.test("instanceof")).toBe(true);
});
it("stanceof is false", () => {
expect(keywordRelationalOperator.test("stanceof")).toBe(false);
});
it("instance is false", () => {
expect(keywordRelationalOperator.test("instance")).toBe(false);
});
it("abc is false", () => {
expect(keywordRelationalOperator.test("abc")).toBe(false);
});
});
});