[project @ 2003-11-06 17:09:50 by simonpj]

[ghc-hetmet.git] / ghc / compiler / hsSyn / HsExpr.lhs

diff --git a/ghc/compiler/hsSyn/HsExpr.lhs b/ghc/compiler/hsSyn/HsExpr.lhs
index 9b2b64f..e484ad7 100644 (file)
--- a/ghc/compiler/hsSyn/HsExpr.lhs
+++ b/ghc/compiler/hsSyn/HsExpr.lhs
@@ -11,23 +11,58 @@ module HsExpr where
 -- friends:
 import HsDecls         ( HsGroup )
 import HsBinds         ( HsBinds(..), nullBinds )
-import HsPat           ( Pat )
-import HsLit           ( HsLit, HsOverLit )
-import HsTypes         ( HsType, PostTcType, SyntaxName )
+import HsPat           ( Pat(..), HsConDetails(..) )
+import HsLit           ( HsLit(..), HsOverLit )
+import HsTypes         ( HsType, PostTcType, SyntaxName, placeHolderType )
 import HsImpExp                ( isOperator, pprHsVar )
 
 -- others:
-import PprType         ( pprParendType )
-import Type            ( Type )
+import Type            ( Type, pprParendType )
 import Var             ( TyVar, Id )
 import Name            ( Name )
 import DataCon         ( DataCon )
 import BasicTypes      ( IPName, Boxity, tupleParens, Fixity(..) )
-import SrcLoc          ( SrcLoc )
+import SrcLoc          ( SrcLoc, generatedSrcLoc )
 import Outputable      
 import FastString
 \end{code}
 
+
+%************************************************************************
+%*                                                                     *
+       Some useful helpers for constructing expressions
+%*                                                                     *
+%************************************************************************
+
+\begin{code}
+mkHsApps    f xs = foldl HsApp (HsVar f) xs
+mkHsVarApps f xs = foldl HsApp (HsVar f) (map HsVar xs)
+
+mkHsIntLit n = HsLit (HsInt n)
+mkHsString s = HsString (mkFastString s)
+
+mkConPat con vars   = ConPatIn con (PrefixCon (map VarPat vars))
+mkNullaryConPat con = ConPatIn con (PrefixCon [])
+
+mkSimpleHsAlt :: Pat id -> HsExpr id -> Match id
+-- A simple lambda with a single pattern, no binds, no guards; pre-typechecking
+mkSimpleHsAlt pat expr 
+  = mkSimpleMatch [pat] expr placeHolderType generatedSrcLoc
+
+mkSimpleMatch :: [Pat id] -> HsExpr id -> Type -> SrcLoc -> Match id
+mkSimpleMatch pats rhs rhs_ty locn
+  = Match pats Nothing (GRHSs (unguardedRHS rhs locn) EmptyBinds rhs_ty)
+
+unguardedRHS :: HsExpr id -> SrcLoc -> [GRHS id]
+unguardedRHS rhs loc = [GRHS [ResultStmt rhs loc] loc]
+
+glueBindsOnGRHSs :: HsBinds id -> GRHSs id -> GRHSs id
+glueBindsOnGRHSs EmptyBinds grhss = grhss
+glueBindsOnGRHSs binds1 (GRHSs grhss binds2 ty)
+  = GRHSs grhss (binds1 `ThenBinds` binds2) ty
+\end{code}
+
+
 %************************************************************************
 %*                                                                     *
 \subsection{Expressions proper}
@@ -156,8 +191,6 @@ data HsExpr id
                                        -- The id is just a unique name to 
                                        -- identify this splice point
 
-  | HsReify (HsReify id)               -- reifyType t, reifyDecl i, reifyFixity
-
   -----------------------------------------------------------
   -- Arrow notation extension
 
@@ -408,7 +441,6 @@ ppr_expr (HsType id) = ppr id
 ppr_expr (HsSplice n e _)    = char '$' <> brackets (ppr n) <> pprParendExpr e
 ppr_expr (HsBracket b _)     = pprHsBracket b
 ppr_expr (HsBracketOut e ps) = ppr e $$ ptext SLIT("where") <+> ppr ps
-ppr_expr (HsReify r)        = ppr r
 
 ppr_expr (HsProc pat (HsCmdTop cmd _ _ _) _)
   = hsep [ptext SLIT("proc"), ppr pat, ptext SLIT("->"), pprExpr cmd]
@@ -597,18 +629,6 @@ data GRHSs id
 data GRHS id
   = GRHS  [Stmt id]            -- The RHS is the final ResultStmt
          SrcLoc
-
-mkSimpleMatch :: [Pat id] -> HsExpr id -> Type -> SrcLoc -> Match id
-mkSimpleMatch pats rhs rhs_ty locn
-  = Match pats Nothing (GRHSs (unguardedRHS rhs locn) EmptyBinds rhs_ty)
-
-unguardedRHS :: HsExpr id -> SrcLoc -> [GRHS id]
-unguardedRHS rhs loc = [GRHS [ResultStmt rhs loc] loc]
-
-glueBindsOnGRHSs :: HsBinds id -> GRHSs id -> GRHSs id
-glueBindsOnGRHSs EmptyBinds grhss = grhss
-glueBindsOnGRHSs binds1 (GRHSs grhss binds2 ty)
-  = GRHSs grhss (binds1 `ThenBinds` binds2) ty
 \end{code}
 
 @getMatchLoc@ takes a @Match@ and returns the
@@ -788,10 +808,11 @@ pprComp brack stmts = brack $
 %************************************************************************
 
 \begin{code}
-data HsBracket id = ExpBr (HsExpr id)
-                 | PatBr (Pat id)
-                 | DecBr (HsGroup id)
-                 | TypBr (HsType id)
+data HsBracket id = ExpBr (HsExpr id)          -- [|  expr  |]
+                 | PatBr (Pat id)              -- [p| pat   |]
+                 | DecBr (HsGroup id)          -- [d| decls |]
+                 | TypBr (HsType id)           -- [t| type  |]
+                 | VarBr id                    -- 'x, ''T
 
 instance OutputableBndr id => Outputable (HsBracket id) where
   ppr = pprHsBracket
@@ -801,26 +822,14 @@ pprHsBracket (ExpBr e) = thBrackets empty (ppr e)
 pprHsBracket (PatBr p) = thBrackets (char 'p') (ppr p)
 pprHsBracket (DecBr d) = thBrackets (char 'd') (ppr d)
 pprHsBracket (TypBr t) = thBrackets (char 't') (ppr t)
-
+pprHsBracket (VarBr n) = char '\'' <> ppr n
+       -- Infelicity: can't show ' vs '', because
+       -- we can't ask n what its OccName is, because the 
+       -- pretty-printer for HsExpr doesn't ask for NamedThings
+       -- But the pretty-printer for names will show the OccName class
 
 thBrackets pp_kind pp_body = char '[' <> pp_kind <> char '|' <+> 
                             pp_body <+> ptext SLIT("|]")
-
-data HsReify id = Reify    ReifyFlavour id     -- Pre typechecking
-               | ReifyOut ReifyFlavour Name    -- Post typechecking
-                                               -- The Name could be the name of
-                                               -- an Id, TyCon, or Class
-
-data ReifyFlavour = ReifyDecl | ReifyType | ReifyFixity
-
-instance Outputable id => Outputable (HsReify id) where
-   ppr (Reify flavour id) = ppr flavour <+> ppr id
-   ppr (ReifyOut flavour thing) = ppr flavour <+> ppr thing
-
-instance Outputable ReifyFlavour where
-   ppr ReifyDecl   = ptext SLIT("reifyDecl")
-   ppr ReifyType   = ptext SLIT("reifyType")
-   ppr ReifyFixity = ptext SLIT("reifyFixity")
 \end{code}
 
 %************************************************************************