re2

re2

A wrapper of the re2 C++ library to demonstrate a use case for spack-rs.

The below syntax guide is reproduced from the re2 codebase.

Regexp Syntax

This module uses the re2 library and hence supports its syntax for regular expressions, which is similar to Perl's with some of the more complicated things thrown away. In particular, backreferences and generalized assertions are not available, nor is \Z.

See Syntax¹ for the syntax supported by RE2, and a comparison with PCRE and PERL regexps.

For those not familiar with Perl's regular expressions, here are some examples of the most commonly used extensions:

• "hello (\\w+) world" -- \w matches a "word" character
• "version (\\d+)" -- \d matches a digit
• "hello\\s+world" -- \s matches any whitespace character
• "\\b(\\w+)\\b" -- \b matches non-empty string at word boundary
• "(?i)hello" -- (?i) turns on case-insensitive matching
• "/\\*(.*?)\\*/" -- .*? matches . minimum number of times possible

The double backslashes are needed when writing string literals. However, they should NOT be used when writing raw string literals:

• r"(hello (\w+) world)" -- \w matches a "word" character
• r"(version (\d+))" -- \d matches a digit
• r"(hello\s+world)" -- \s matches any whitespace character
• r"(\b(\w+)\b)" -- \b matches non-empty string at word boundary
• r"((?i)hello)" -- (?i) turns on case-insensitive matching
• r"(/\*(.*?)\*/)" -- .*? matches . minimum number of times possible

When using UTF-8 encoding, case-insensitive matching will perform simple case folding, not full case folding.

License

BSD-3-Clause, in order to match re2's license.

Footnotes

1. https://github.com/google/re2/wiki/Syntax ↩