import {-# SOURCE #-} HsExpr ( SyntaxExpr )
-- friends:
-import HsBinds ( DictBinds, HsBind(..), ExprCoFn, isIdCoercion, emptyLHsBinds, pprLHsBinds )
+import HsBinds ( DictBinds, HsBind(..), ExprCoFn, isIdCoercion, pprCoFn,
+ emptyLHsBinds, pprLHsBinds )
import HsLit ( HsLit(HsCharPrim), HsOverLit )
import HsTypes ( LHsType, PostTcType )
import BasicTypes ( Boxity, tupleParens )
------------ Dictionary patterns (translation only) ---------------
| DictPat -- Used when destructing Dictionaries with an explicit case
- [id] -- superclass dicts
- [id] -- methods
+ [id] -- Superclass dicts
+ [id] -- Methods
------------ Pattern coercions (translation only) ---------------
| CoPat ExprCoFn -- If co::t1 -> t2, p::t2,
-- then (CoPat co p) :: t1
- (Pat id) -- No nested location reqd
- Type
+ (Pat id) -- Why not LPat? Ans: existing locn will do
+ Type
+ -- During desugaring a (CoPat co pat) turns into a cast with 'co' on
+ -- the scrutinee, followed by a match on 'pat'
\end{code}
HsConDetails is use both for patterns and for data type declarations
pprPat (NPat l (Just _) _ _) = char '-' <> ppr l
pprPat (NPlusKPat n k _ _) = hcat [ppr n, char '+', ppr k]
pprPat (TypePat ty) = ptext SLIT("{|") <> ppr ty <> ptext SLIT("|}")
-pprPat (CoPat co pat _) = parens (ppr co) <+> ptext SLIT("`cast`") <+> ppr pat
+pprPat (CoPat co pat _) = parens (pprCoFn (ppr pat) co)
pprPat (SigPatIn pat ty) = ppr pat <+> dcolon <+> ppr ty
pprPat (SigPatOut pat ty) = ppr pat <+> dcolon <+> ppr ty
pprPat (DictPat ds ms) = parens (sep [ptext SLIT("{-dict-}"),