regexlint 2.0

Linter for (Pygments) regular expressions

Regexlint is intended to be run as a linter against an importable Pygments lexer, and flag problems that will prevent the lexer from performing well (since we don’t have branch coverage for lexers :)

As a simple example, alternations are first match, so it will flag this as never matching “elseif”:

(else|elseif)

It also understands some Pygments internals, for example bygroups(...)` needs to have the same number of args as the regex has capture groups. Too many will result in duplicate text; too few will result in missing text. There should also not be any gaps between the capture groups, so this example flags two problems:

(r'(foo)\s+(bar)', bygroups(Blah)),

Usage

make demo
    or
regexlint pygments.lexers.web:HtmlLexer
    or
python3 regexlint/cmdline.py pygments.lexers.web

Todo

• Figure out which phase should remove unnecessary backslashes

• Write the alternation expander, so that ([ax]|a[bc]) fails the alternation order checks

• Make more general than just for Pygments

License

This project is licensed under the Apache Public License, see COPYING