logos_derive melts the CPU for XID, then gets a SIGKILL

[Evrey]

Given this token rule:

    #[regex = r"\p{XID_Start}\p{XID_Continue}*"]
    LiteralIdentifier,

… logos will spin up a single CPU core to 100%, then receive a SIGKILL if the core overheats. Otherwise, when my laptop manages to keep the core from overheating, compilation seems to take a billion years. Well, at least 5min. I Ctrl+Cd out of impatience. RAM usage is pretty low, though.

So things that might help:

• Find opportunities to parallelise the work.
• Figure out when work takes too long and maybe sleep for a little or be nice.
• Whatever else helps getting this beast to work.

Until then I'll have to use ASCII identifiers. ),:

Edit: Using v0.9.7 from https://crates.io/

Edit 2: Compilation never seems to finish. With successful cooling, the core still overheats. And logos starts using a lot of RAM, so might also be related to #78 .

[Evrey]

#78 and this one can be merged. When trying to compile something with quite the state explosion, the CPUs spin up to 100%, and memory usage grows exponentially. When compiling with -j 1, logos builds slowly enough for me to not overheat the CPU, then continues to consume enough RAM so that everything hangs thanks to excessive thrashing.

[maciejhirsz]

Aggregate into #70.