119 lines
3.1 KiB
JavaScript
Executable File
119 lines
3.1 KiB
JavaScript
Executable File
// 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 { Parser } from "./state";
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import { types as tt } from "./tokentype";
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import { lineBreak } from "./whitespace";
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export class TokContext {
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constructor(token, isExpr, preserveSpace, override) {
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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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}
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export const types = {
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b_stat: new TokContext("{", false),
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b_expr: new TokContext("{", true),
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b_tmpl: new TokContext("${", true),
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p_stat: new TokContext("(", false),
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p_expr: new TokContext("(", true),
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q_tmpl: new TokContext("`", true, true, p => p.readTmplToken()),
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f_expr: new TokContext("function", true)
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};
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const pp = Parser.prototype;
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pp.initialContext = function () {
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return [types.b_stat];
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};
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pp.braceIsBlock = function (prevType) {
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if (prevType === tt.colon) {
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let parent = this.curContext();
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if (parent === types.b_stat || parent === types.b_expr)
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return !parent.isExpr;
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}
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if (prevType === tt._return)
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return lineBreak.test(this.input.slice(this.lastTokEnd, this.start));
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if (prevType === tt._else || prevType === tt.semi || prevType === tt.eof)
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return true;
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if (prevType === tt.braceL)
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return this.curContext() === types.b_stat;
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return !this.exprAllowed;
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};
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pp.updateContext = function (prevType) {
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let update, type = this.type;
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if (type.keyword && prevType === tt.dot) {
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this.exprAllowed = false;
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} else if (update = type.updateContext) {
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update.call(this, prevType);
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} else {
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this.exprAllowed = type.beforeExpr;
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}
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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.context.length === 1) {
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this.exprAllowed = true;
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return;
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}
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let out = this.context.pop();
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if (out === types.b_stat && this.curContext() === types.f_expr) {
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this.context.pop();
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this.exprAllowed = false;
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} else if (out === types.b_tmpl) {
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this.exprAllowed = true;
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} else {
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this.exprAllowed = !out.isExpr;
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}
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};
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tt.braceL.updateContext = function (prevType) {
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this.context.push(this.braceIsBlock(prevType) ? types.b_stat : types.b_expr);
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this.exprAllowed = true;
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};
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tt.dollarBraceL.updateContext = function () {
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this.context.push(types.b_tmpl);
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this.exprAllowed = true;
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};
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tt.parenL.updateContext = function (prevType) {
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let statementParens = prevType === tt._if || prevType === tt._for || prevType === tt._with || prevType === tt._while;
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this.context.push(statementParens ? types.p_stat : types.p_expr);
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this.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.b_stat) {
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this.context.push(types.f_expr);
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}
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this.exprAllowed = false;
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};
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tt.backQuote.updateContext = function () {
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if (this.curContext() === types.q_tmpl) {
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this.context.pop();
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} else {
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this.context.push(types.q_tmpl);
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}
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this.exprAllowed = false;
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};
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