base provide stripPrefix since at least 4.9

Author: Shimuuar

vector/tests/Boilerplater.hs

@@ -1,5 +1,6 @@
 module Boilerplater where
 
+import Data.List (stripPrefix)
 import Test.Tasty.QuickCheck
 
 import Language.Haskell.TH
@@ -8,20 +9,4 @@ import Language.Haskell.TH
 testProperties :: [Name] -> Q Exp
 testProperties nms = fmap ListE $ sequence [[| testProperty $(stringE prop_name) $(varE nm) |]
                                            | nm <- nms
-                                           , Just prop_name <- [stripPrefix_maybe "prop_" (nameBase nm)]]
-
--- This nice clean solution doesn't quite work since I need to use lexically-scoped type
--- variables, which aren't supported by Template Haskell. Argh!
--- testProperties :: Q [Dec] -> Q Exp
--- testProperties mdecs = do
---     decs <- mdecs
---     property_exprs <- sequence [[| testProperty "$prop_name" $(return $ VarE nm) |]
---                                | FunD nm _clauses <- decs
---                                , Just prop_name <- [stripPrefix_maybe "prop_" (nameBase nm)]]
---     return $ LetE decs (ListE property_exprs)
-
-stripPrefix_maybe :: String -> String -> Maybe String
-stripPrefix_maybe prefix what
-  | what_start == prefix = Just what_end
-  | otherwise            = Nothing
-  where (what_start, what_end) = splitAt (length prefix) what
+                                           , Just prop_name <- [stripPrefix "prop_" (nameBase nm)]]