The Haskell GHC compiler supports the syntax to specify "rewrite rules", usually written in library code:

http://www.haskell.org/ghc/docs/7.0.3/html/users_guide/rewrite-rules.html

http://hackage.haskell.org/trac/ghc/wiki/RewriteRules

http://www.haskell.org/haskellwiki/GHC/Using_rules

They are rules that the compiler follows blindly hopefully to simplify and speed up the Haskell code. D increasingly contains higher order operators and other higher order constructs, so is it a good idea to add the support for similar rules written down in D library code (mostly Phobos)?

Bye,
bearophile