jsDump bug

[dmajda]

The following grammar entered into the online version:

start = { return { item: 'abc' }; }

produces output [] for an empty input, instead of correct { item: 'abc' }.

The following grammars don't have this problem:

start = { return { item: 0 }; }

start = { return { index: 'abc' }; }

Debugging points to a bug in the jsDump library. I need to look whether this is fixed in a newer version. If not, I need to report it/fix it.

Originally reported in the Google Group.

[reverofevil]

The problem is that jsDump is using perfectly wrong approach of sniffing object's properties, and doesn't rely on types at all. The correct solution is described here (http://javascriptweblog.wordpress.com/2011/08/08/fixing-the-javascript-typeof-operator/). Hotfix pushed to my fork, though we'd better look for another solution like running pegjs into js.js (https://github.com/jterrace/js.js), so that return value will be consistent, and there will be Function.prototype.toSource support in any browser (though, 200 times slowlier :).

[dmajda]

According to this post this bug can be fixed by using a jsDump fork.

[dmajda]

Hmm, I thought upgrading jsDump solved the problem, but it did that only for item. Dumping still misbehaves in presence of the callee property, as demonstrated by the following grammar:

start = "" { return { callee: 0 }; }

With empty input, it produces [].

[dmajda]

I reported the bug at the jsDump fork the website uses and provided a PR with a fix. I’ll apply the fix locally too.