regexplain

A terminal UI for explaining and visualizing regular expressions, kindof like regex101.

regexplain [OPTIONS]

  -p, --pattern <PATTERN>              regex pattern
  -t, --text-to-match <TEXT_TO_MATCH>  text to match against
  -f, --file-to-match <FILE_TO_MATCH>  read text to match from file
  -n, --no-tui                         run in CLI mode (no TUI)
  -r, --restore                        restore previous TUI session
  -h, --help                           print help
  -V, --version                        print version

Design

I structured it in such a way that it first parses raw and verbose AST (currently only from regex_syntax) into a simplified form and all the other modules, (description generator, colorizer) work on top of that simplified intermediate form. I did this to so that we may easily add a regex flavours later (only rust-flavoured regex right now).

Usage

You can download the binary from release or if you have cargo

cargo install --git https://github.com/kapilpokhrel/regexplain

Controls

Key	Action
Esc / Ctrl+C	Save state and quit
Shift+Tab	Cycle focus (Pattern → Text → Desc Tree)
Click	Focus the clicked panel
Ctrl+Y	Copy pattern to clipboard (when focused on pattern input)
j/k/h/l or Arrows	Navigate desctree (desctree focused)
Ctrl+N	Scroll viewport down (desctree focused)
Ctrl+J	Scroll viewport up (desctree focused)

Also, both input and match editor window use tui-textarea2, so we get Emacs-style bindings (C-f/C-b, C-n/C-p, M-f/M-b, C-a/C-e, C-d/C-h, C-k, M-</M->, etc.). The pattern input is single-line (Enter disabled).

I'm still getting the hang of Rust, so the code might not always be the most idiomatic. This project also went through a lot of iterations (and pauses) — you might smell some of that in places.