Language.Haskell.Exts.QQ

This module defines quasiquoters for haskell-src-exts expressions and declarations.

Antiquotations steal the splice syntax of Template Haskell, so for example example x appears antiquoted in [$hs| $x ++ $(Hs.strE "bar") |]. Expressions appearing inside parenthesized splices are limited to concrete syntax expressible by Template Haskell's Exp data type.

Names in patterns can also be antiquoted, using double parentheses. For instance:

 let x = Hs.name "n" in [hs| \ ((x)) -> $(Hs.Var (Hs.UnQual x)) + 1 |]

Alternatively, one can use the double underscore syntax, useful when antiquoting a function name as in the following:

 let f = "incr"
     fE = Hs.Var $ Hs.UnQual $ Hs.name f
 in [hs| let __f__ x = x + 1 in $fE 10 |]

In a pattern context, antiquotations use the same syntax.

Documentation

hs :: QuasiQuoter

A quasiquoter for expressions. All Haskell extensions known by haskell-src-exts are activated by default.

dec :: QuasiQuoter

A quasiquoter for top-level declarations.

ty :: QuasiQuoter

A quasiquoter for types. All Haskell extensions known by haskell-src-exts are activated by default.

hsWithMode :: ParseMode -> QuasiQuoter

Rather than importing the above quasiquoters, one can create custom quasiquoters with a customized ParseMode using this function.

 hs = hsWithMode mode
 dec = decWithMode mode

decWithMode :: ParseMode -> QuasiQuoter

tyWithMode :: ParseMode -> QuasiQuoter