Library for regexes?

[amber ivy]

I'm looking for a library that can do regex matches, including unlimited-length lookbehinds. Unfortunately, regex, fancy-regex, and pcre2 don't support it. Any ideas where to look? Looking for something like the regex library (not re) from Python, but... ya'know, Rust. Crate suggestions would be appreciated!

[cyan patio]

What about https://crates.io/crates/onig ?

[amber ivy]

Seemed promising. But, I'm getting this on build. I found something suggesting clang, but it's already installed (I'm on Linux):

error: failed to run custom build command for `onig_sys v69.8.1`

Caused by:
  process didn't exit successfully: `/(REMOVED)/target/debug/build/onig_sys-3d7339d14aefcb54/build-script-build` (exit status: 101)
  --- stdout
  cargo:rerun-if-env-changed=RUSTONIG_DYNAMIC_LIBONIG
  cargo:rerun-if-env-changed=RUSTONIG_STATIC_LIBONIG
  cargo:rerun-if-env-changed=RUSTONIG_SYSTEM_LIBONIG

  --- stderr
  thread 'main' panicked at /(REMOVED)/.cargo/registry/src/index.crates.io-6f17d22bba15001f/bindgen-0.59.2/src/ir/context.rs:878:9:
  "OnigValue_struct_(unnamed_at_oniguruma/src/oniguruma_h_786_3)" is not a valid Ident
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[cyan patio]

Try onig = { version = "6", default-features = false }

The other workaround is ```rs
[dependencies]
onig = { git = "https://github.com/rust-onig/rust-onig", revision = "fa90c0e97e90a056af89f183b23cd417b59ee6a2" }

[patch.crates-io]
onig_sys = { git = "https://github.com/rust-onig/rust-onig", revision = "fa90c0e97e90a056af89f183b23cd417b59ee6a2" }

[amber ivy]

That got it to build, so thank you! Sadly, it still doesn't seem to support the regex Error(OnigError(-122), invalid pattern in look-behind) :-(

Maybe it's an XY Problem, but that would be hard

[cyan patio]

If onig doesn't support it I doubt anything will. Ruby is known as having a really lenient Regex system

[amber ivy]

Fair enough, I'll try to optimize Python then. Thanks anyways! Re-writing the regex would be too hard in this case

[cyan patio]

fair warning that regexes with this type of thing are insanely expensive to run

they easily get into exponential time

[amber ivy]

Yeah... that was the "XY problem" part, to an extent. The real solution is fix the regex, probably. But that's hard here

[stable pollen]

can you show the regex, then?