107 lines
2.9 KiB
JavaScript
107 lines
2.9 KiB
JavaScript
// @flow
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// The algorithm used to determine whether a regexp can appear at a
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// given point in the program is loosely based on sweet.js' approach.
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// See https://github.com/mozilla/sweet.js/wiki/design
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import { types as tt } from "./types";
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import { lineBreak } from "../util/whitespace";
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export class TokContext {
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constructor(
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token: string,
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isExpr?: boolean,
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preserveSpace?: boolean,
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override?: Function,
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) {
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this.token = token;
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this.isExpr = !!isExpr;
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this.preserveSpace = !!preserveSpace;
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this.override = override;
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}
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token: string;
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isExpr: boolean;
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preserveSpace: boolean;
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override: ?Function;
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}
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export const types: {
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[key: string]: TokContext;
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} = {
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braceStatement: new TokContext("{", false),
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braceExpression: new TokContext("{", true),
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templateQuasi: new TokContext("${", true),
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parenStatement: new TokContext("(", false),
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parenExpression: new TokContext("(", true),
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template: new TokContext("`", true, true, (p) => p.readTmplToken()),
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functionExpression: new TokContext("function", true)
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};
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// Token-specific context update code
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tt.parenR.updateContext = tt.braceR.updateContext = function () {
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if (this.state.context.length === 1) {
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this.state.exprAllowed = true;
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return;
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}
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const out = this.state.context.pop();
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if (out === types.braceStatement && this.curContext() === types.functionExpression) {
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this.state.context.pop();
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this.state.exprAllowed = false;
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} else if (out === types.templateQuasi) {
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this.state.exprAllowed = true;
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} else {
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this.state.exprAllowed = !out.isExpr;
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}
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};
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tt.name.updateContext = function (prevType) {
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this.state.exprAllowed = false;
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if (prevType === tt._let || prevType === tt._const || prevType === tt._var) {
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if (lineBreak.test(this.input.slice(this.state.end))) {
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this.state.exprAllowed = true;
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}
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}
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};
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tt.braceL.updateContext = function (prevType) {
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this.state.context.push(this.braceIsBlock(prevType) ? types.braceStatement : types.braceExpression);
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this.state.exprAllowed = true;
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};
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tt.dollarBraceL.updateContext = function () {
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this.state.context.push(types.templateQuasi);
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this.state.exprAllowed = true;
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};
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tt.parenL.updateContext = function (prevType) {
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const statementParens = prevType === tt._if || prevType === tt._for ||
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prevType === tt._with || prevType === tt._while;
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this.state.context.push(statementParens ? types.parenStatement : types.parenExpression);
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this.state.exprAllowed = true;
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};
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tt.incDec.updateContext = function () {
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// tokExprAllowed stays unchanged
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};
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tt._function.updateContext = function () {
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if (this.curContext() !== types.braceStatement) {
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this.state.context.push(types.functionExpression);
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}
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this.state.exprAllowed = false;
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};
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tt.backQuote.updateContext = function () {
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if (this.curContext() === types.template) {
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this.state.context.pop();
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} else {
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this.state.context.push(types.template);
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}
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this.state.exprAllowed = false;
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};
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