Fast string lookup in a single `&str`, containing millions of unevenly sized substrings

[BurntSushi]

@alexpovel

I had looked into prefix trees/tries but deserializing them at runtime turned out too slow, at least in the naive ways.

In addition to the fst crate, regex-automata provides a way to build a fully compiled DFA. It also supports zero-copy deserialization. You won't get the compression that fst gives you, but lookup speed is likely faster.