| License | BSD-3-CLAUSE |
|---|---|
| Maintainer | Jamie Willis |
| Stability | stable |
| Safe Haskell | None |
| Language | Haskell2010 |
Parsley.OverloadedQuotesPlugin
Description
This plugin hijacks the regular Haskell syntax
for Untyped Template Haskell (UTH). Since parsley uses Typed
Template Haskell (TTH), it is unlikely that a user of the library will
need to be using UTH in the same file (with the possible exception of
top-level splices, or quotes other than the basic [|x|]). This plugin
will transform every UTH quote in a file so that it represents a value of
Quapplicative q => q a. This transformation is as follows:
qsucc :: Quapplicative q => q Int -> q Int qsucc qx = [|$(qx) + 1|] -- goes to: qsucc qx = makeQ (_val qx + 1) [||$$(_code qx) + 1||]
Values of Parsley.Defunctionalized.Defunc can also be spliced in directly:
diffcons :: Defunc a -> Defunc ([a] -> [a]) -> Defunc ([a] -> [a]) diffcons qx qdxs = [| $(COMPOSE) ($(CONS) $(qx)) $(qdxs) |]
And lambda abstraction works too (along with any other syntax):
diffcons' :: Defunc (a -> ([a] -> [a]) -> [a] -> [a]) diffcons' = [|\x dxs -> $(diffcons [|x|] [|dxs|])|]
The disadvantage to this plugin currently is that it does not make any
attempt to leverage the specialised parts of Defunc to improve the code
generation and inspectibility. The user would be left to use this manually.