Exponential performance drop when deeply nesting parse trees (Repeat, Function, Parentheses) about rpgdice HOT 1 OPEN

I wonder if it's related to this:

pegjs/pegjs#237

So, for the moment, I'm not that worried, since we have the ability to store a parsed tree, and call it as many times as we want to get unique output values. However, I'll have to make it clear in the documentation that for performance reasons, users will want to cache parsed rolls.

Hmm. Also might need to check Variable, and make sure it updates if the scope changes between eval calls.

Might even consider shipping a built-in cache, if performance is going to be poor enough. Thanks for finding this; we should probably build a small benchmarking util (can even run it between versions and store that off) and come up with as many real-worldish strings as possible to test. If we can handle, say most of the rolls from D&D 5e, 4e, and 3.5e without caching, then we're probably fine.

(I have a half dozen 4e and 3.5e characters stored in sqlite with their roll texts; I can scrape some of that for this. We might have to build the rest by hand. Off the top of my head, I don't remember which class/spell/power has the largest, weirdest ruleset.)

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