Infinite loop during GAST builder.

By making this change and returning a number, I was able to make chevrotain fall into an infinite loop:

If you need more code to debug this, please clone this branch. These should be the only important lines here, as Block is the starting rule.

[bd82]

Well, I must say you have a real talent for finding edge cases @kdex 👍

Looks like the regExp I was using to match string literals included a redundant “+” modifier Which caused exponential performance degradation when matching unclosed literals.

/'([^\\']+|\\([bfnrtv'\\/]|u[0-9a-fA-F]{4}))*'/

See JSPerf: https://jsperf.com/regexp-v8-perf

[bd82]

I normally try to avoid “ifs” in hot spots in the code. But this could possibly be checked optionally using a JavaScript noop pattern when DevMode is enabled.

• noop pattern means calling a function that has an empty implementation in certain flows. So in those flows it gets in-lined and effectively has no negative impact on runtime.

I still need to investigate if this can occur in less “strange” circumstance first though.