GroteTrap
From HaskellWiki
GroteTrap allows you to quickly define expression languages. It is available for download on Hackage.
An example:
data Logic = Var String | Or [Logic] | And [Logic] | Impl Logic Logic | Not Logic deriving (Show, Eq) logicLanguage :: Language Logic logicLanguage = language { variable = Var , operators = [ Unary Not Prefix 0 "!" , Nary And True 1 "&&" , Nary Or True 2 "||" , Binary Impl InfixR 3 "->" ] }
With this, we can do:
> readExpression logicLanguage "p && q" And [Var "p",Var "q"]
