[duaneb]

A lot of optimizations on arbitrary byte code often look for patterns in byte streams (or in reified assembly) in similar ways to regexes.

[teraflop]

For many years, an important stage of the GHC Haskell compiler consisted of a giant Perl script full of regexes.

http://code.haskell.org/ghc-scp/ghc/docs/comm/the-beast/mang...