Fixed null pointer exception for JS target

[harrytallbelt]

For JavaScript target, getToken and getChild methods in ParserRuleContext.js did not check if this.children is null as code for Java target did. I added the two if statements Java implementation has in these methods.

For an example of where the problem arises, consider the rule

program : /* nothing */ | statements ;

If the input is empty (i.e. statements is not matched), the visitor's method

ProgramBaseVisitor.prototype.visitProgram = function(ctx) {
  return { statements: ctx.statements() ? this.visit(ctx.statements()) : [] }
}

fails on the ctx.statements() call, because of an attempt to access this.children.length in ParserRuleContext.js's getChild method.

Meanwhile, the Java implementation of the same thing has no problem calling ctx.statements().

[parrt]

@ericvergnaud blessed?

[ericvergnaud]

Yep Envoyé de mon iPhone

…

Le 9 mars 2017 à 01:54, Terence Parr ***@***.***> a écrit : @ericvergnaud blessed? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread.