8000 implement switch-case parser · repos-javascript-compilers/JSX@3268348 · GitHub
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kazuhokazuho
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implement switch-case parser
1 parent c6870e7 commit 3268348

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3 files changed

+83
-4
lines changed

3 files changed

+83
-4
lines changed

‎example/fib.jsx

Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -25,4 +25,15 @@ class Fib {
2525
}
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return value;
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}
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static function fib4(n : Int) : Int {
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switch (n) {
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case 1:
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return 1;
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case 2:
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return 1;
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default:
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return Fib.fib4(n - 1) + Fib.fib4(n - 2);
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}
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}
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}

‎lib/Parser.js

Lines changed: 58 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -21,6 +21,7 @@ var IfStatement = require("./IfStatement");
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var LabelStatement = require("./LabelStatement");
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var LogStatement = require("./LogStatement");
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var ReturnStatement = require("./ReturnStatement");
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var SwitchStatement = require("./SwitchStatement");
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var WhileStatement = require("./WhileStatement");
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var AdditiveExpression = require("./AdditiveExpression");
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var ArrayExpression = require("./ArrayExpression");
@@ -178,6 +179,14 @@ var Parser = module.exports = Class.extend({
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return identifier;
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},
180181

182+
_expectIsNotEOF: function () {
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if (this._isEOF()) {
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this._newError("unexpected EOF");
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return false;
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}
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return true;
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},
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_skipStatement: function () {
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var token;
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while ((token = this._nextToken()) != null) {
@@ -359,10 +368,8 @@ var Parser = module.exports = Class.extend({
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_block: function () {
361370
while (this._expectKeywordOpt("}") == null) {
362-
if (this._isEOF()) {
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this._newError("unexpected EOF");
371+
if (! this._expectIsNotEOF())
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break;
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}
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if (! this._statement())
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this._skipStatement();
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}
@@ -582,7 +589,54 @@ var Parser = module.exports = Class.extend({
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},
583590

584591
_switchStatement: function () {
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return false; // FIXME
592+
var expr = this._expr(false);
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if (expr == null)
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return false;
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if (this._expectKeyword("{") == null)
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return null;
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var caseExprs = []; // array of [ label, statementIndex ]
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var defaultStatementIndex = -1;
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// caseblock
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var statementBase = this._statements.length;
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while (this._expectKeywordOpt("}") == null) {
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if (! this._expectIsNotEOF())
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return false;
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var caseOrDefault;
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if (caseExprs.length == 0 && defaultStatementIndex == 1) {
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// first statement within the block should start with a label
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if ((caseOrDefault = this._expectKeyword([ "case", "default" ])) == null)
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return false;
609+
} else {
610+
caseOrDefault = this._expectKeywordOpt([ "case", "default" ]);
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}
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switch (caseOrDefault) {
613+
case "case":
614+
var labelExpr = this._expr();
615+
if (labelExpr == null)
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return false;
617+
if (this._expectKeyword(":") == null)
618+
return false;
619+
caseExprs.push([ labelExpr, this._statements.length - statementBase ]);
620+
break;
621+
case "default":
622+
if (this._expectKeyword(":") == null)
623+
return false;
624+
if (defaultStatementIndex != -1) {
625+
this._newError("cannot have more than one default statement within one switch block");
626+
return false;
627+
}
628+
defaultStatementIndex = this._statements.length - statementBase;
629+
break;
630+
default:
631+
if (! this._statement())
632+
this._skipStatement();
633+
break;
634+
}
635+
}
636+
// done
637+
var subStatements = this._statements.splice(statementBase);
638+
this._statements.push(new SwitchStatement(expr, caseExprs, defaultStatementIndex, subStatements));
639+
return true;
586640
},
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588642
_throwStatement: function () {

‎lib/SwitchStatement.js

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
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"use strict";
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var Statement = require("./Statement");
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var SwitchStatement = module.exports = Statement.extend({
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7+
initialize: function (expr, caseExpr, defaultStatementIndex, statements) {
8+
this._expr = expr;
9+
this._caseExpr = caseExpr;
10+
this._defaultStatementIndex = defaultStatementIndex;
11+
this._statements = statements;
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}
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});

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