Infinite loops in expressions crash the fiddle and homepage on pest.rs

[LewisHein5]

How to reproduce:

• 1 For your sanity, open an anonymous browsing window.
• 2 Navigate to https://pest.rs/#editor
• 3 Enter the following text into the editor: field = {"-"? ~ PUSH("."?) ~ (ASCII_DIGIT | PEEK)+}
• 4 The page will become unresponsive, I assume it is stuck running an infinite loop in the WASM VM but have not tested this hypothesis.

[LewisHein5]

Note: Because the user's last expression is saved in local storage, there is no way to recover from this short of erasing local storage for pest.rs. Hence the suggestion to use an anonymous browsing window.

[tomtau]

@nathanielknight @Jamalam360 @LeoDog896 @huacnlee @birkenfeld could pest_vm perhaps execute in a webworker with a timeout?

[tristan-f-r]

@nathanielknight @Jamalam360 @LeoDog896 @huacnlee @birkenfeld could pest_vm perhaps execute in a webworker with a timeout?

That's a good idea! I'll try making a PR.