%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[MatchLit]{Pattern-matching literal patterns}
\begin{code}
-#include "HsVersions.h"
-
module MatchLit ( matchLiterals ) where
-IMP_Ubiq()
-IMPORT_DELOOPER(DsLoop) -- break match-ish and dsExpr-ish loops
+#include "HsVersions.h"
-import HsSyn ( HsLit(..), OutPat(..), HsExpr(..),
- Match, HsBinds, Stmt, Qualifier, PolyType, ArithSeqInfo )
-import TcHsSyn ( TypecheckedHsExpr(..), TypecheckedHsBinds(..),
- TypecheckedPat(..)
- )
-import CoreSyn ( SYN_IE(CoreExpr), SYN_IE(CoreBinding) )
+import {-# SOURCE #-} Match ( match )
+import {-# SOURCE #-} DsExpr ( dsExpr )
+
+import HsSyn ( HsLit(..), OutPat(..), HsExpr(..) )
+import TcHsSyn ( TypecheckedHsExpr, TypecheckedPat )
+import CoreSyn ( Expr(..), Bind(..) )
+import Id ( Id )
import DsMonad
import DsUtils
-import Literal ( mkMachInt, Literal(..) )
+import Const ( mkMachInt, Literal(..) )
+import PrimRep ( PrimRep(IntRep) )
import Maybes ( catMaybes )
-import Type ( isPrimType )
-import Util ( panic, assertPanic )
+import Type ( Type, isUnLiftedType )
+import Panic ( panic, assertPanic )
\end{code}
\begin{code}
matchLiterals :: [Id]
-> [EquationInfo]
- -> [EquationInfo] -- Shadows
-> DsM MatchResult
\end{code}
the alts---here we use @match_prims_used@.
\begin{code}
-matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo (LitPat literal lit_ty : ps1) _ : eqns) shadows
+matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal lit_ty : ps1) _ : eqns)
= -- GENERATE THE ALTS
- match_prims_used vars eqns_info shadows `thenDs` \ prim_alts ->
+ match_prims_used vars eqns_info `thenDs` \ prim_alts ->
-- MAKE THE PRIMITIVE CASE
- mkCoPrimCaseMatchResult var prim_alts
+ returnDs (mkCoPrimCaseMatchResult var prim_alts)
where
- match_prims_used _ [{-no more eqns-}] _ = returnDs []
+ match_prims_used _ [{-no more eqns-}] = returnDs []
- match_prims_used vars eqns_info@(EqnInfo ((LitPat literal lit_ty):ps1) _ : eqns) shadows
+ match_prims_used vars eqns_info@(EqnInfo n ctx ((LitPat literal lit_ty):ps1) _ : eqns)
= let
(shifted_eqns_for_this_lit, eqns_not_for_this_lit)
- = partitionEqnsByLit literal eqns_info
- (shifted_shadows_for_this_lit, shadows_not_for_this_lit)
- = partitionEqnsByLit literal shadows
+ = partitionEqnsByLit Nothing literal eqns_info
in
-- recursive call to make other alts...
- match_prims_used vars eqns_not_for_this_lit shadows_not_for_this_lit `thenDs` \ rest_of_alts ->
+ match_prims_used vars eqns_not_for_this_lit `thenDs` \ rest_of_alts ->
-- (prim pats have no args; no selectMatchVars as in match_cons_used)
-- now do the business to make the alt for _this_ LitPat ...
- match vars shifted_eqns_for_this_lit shifted_shadows_for_this_lit `thenDs` \ match_result ->
+ match vars shifted_eqns_for_this_lit `thenDs` \ match_result ->
returnDs (
(mk_core_lit lit_ty literal, match_result)
: rest_of_alts
mk_core_lit ty (HsStringPrim s) = MachStr s
mk_core_lit ty (HsFloatPrim f) = MachFloat f
mk_core_lit ty (HsDoublePrim d) = MachDouble d
- mk_core_lit ty (HsLitLit s) = ASSERT(isPrimType ty)
- MachLitLit s (panic "MatchLit.matchLiterals:mk_core_lit:HsLitLit; typePrimRep???")
+ mk_core_lit ty (HsLitLit s) = ASSERT(isUnLiftedType ty)
+ MachLitLit s ty
mk_core_lit ty other = panic "matchLiterals:mk_core_lit:unhandled"
\end{code}
\begin{code}
-matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo ((NPat literal lit_ty eq_chk):ps1) _ : eqns) shadows
+matchLiterals all_vars@(var:vars)
+ eqns_info@(EqnInfo n ctx ((NPat literal lit_ty eq_chk):ps1) _ : eqns)
= let
(shifted_eqns_for_this_lit, eqns_not_for_this_lit)
- = partitionEqnsByLit literal eqns_info
- (shifted_shadows_for_this_lit, shadows_not_for_this_lit)
- = partitionEqnsByLit literal shadows
+ = partitionEqnsByLit Nothing literal eqns_info
+ in
+ dsExpr (HsApp eq_chk (HsVar var)) `thenDs` \ pred_expr ->
+ match vars shifted_eqns_for_this_lit `thenDs` \ inner_match_result ->
+ let
+ match_result1 = mkGuardedMatchResult pred_expr inner_match_result
in
- dsExpr (HsApp eq_chk (HsVar var)) `thenDs` \ pred_expr ->
- match vars shifted_eqns_for_this_lit shifted_shadows_for_this_lit `thenDs` \ inner_match_result ->
- mkGuardedMatchResult pred_expr inner_match_result `thenDs` \ match_result1 ->
-
if (null eqns_not_for_this_lit)
then
returnDs match_result1
else
- matchLiterals all_vars eqns_not_for_this_lit shadows_not_for_this_lit `thenDs` \ match_result2 ->
- combineMatchResults match_result1 match_result2
+ matchLiterals all_vars eqns_not_for_this_lit `thenDs` \ match_result2 ->
+ returnDs (combineMatchResults match_result1 match_result2)
\end{code}
For an n+k pattern, we use the various magic expressions we've been given.
<try-next-pattern-or-whatever>
\end{verbatim}
-Given a blob of LitPats/NPats, we want to split them into those
+
+\begin{code}
+matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx ((NPlusKPat master_n k ty ge sub):ps1) _ : eqns)
+ = let
+ (shifted_eqns_for_this_lit, eqns_not_for_this_lit)
+ = partitionEqnsByLit (Just master_n) k eqns_info
+ in
+ match vars shifted_eqns_for_this_lit `thenDs` \ inner_match_result ->
+
+ dsExpr (HsApp ge (HsVar var)) `thenDs` \ ge_expr ->
+ dsExpr (HsApp sub (HsVar var)) `thenDs` \ nminusk_expr ->
+
+ let
+ match_result1 = mkGuardedMatchResult ge_expr $
+ mkCoLetsMatchResult [NonRec master_n nminusk_expr] $
+ inner_match_result
+ in
+ if (null eqns_not_for_this_lit)
+ then
+ returnDs match_result1
+ else
+ matchLiterals all_vars eqns_not_for_this_lit `thenDs` \ match_result2 ->
+ returnDs (combineMatchResults match_result1 match_result2)
+\end{code}
+
+Given a blob of @LitPat@s/@NPat@s, we want to split them into those
that are ``same''/different as one we are looking at. We need to know
-whether we're looking at a LitPat/NPat, and what literal we're after.
+whether we're looking at a @LitPat@/@NPat@, and what literal we're after.
\begin{code}
-partitionEqnsByLit :: HsLit
+partitionEqnsByLit :: Maybe Id -- (Just v) for N-plus-K patterns, where v
+ -- is the "master" variable;
+ -- Nothing for NPats and LitPats
+ -> HsLit
-> [EquationInfo]
-> ([EquationInfo], -- These ones are for this lit, AND
-- they've been "shifted" by stripping
-- are exactly as fed in.
)
-partitionEqnsByLit lit eqns
+partitionEqnsByLit nPlusK lit eqns
= ( \ (xs,ys) -> (catMaybes xs, catMaybes ys))
- (unzip (map (partition_eqn lit) eqns))
+ (unzip (map (partition_eqn nPlusK lit) eqns))
where
- partition_eqn :: HsLit -> EquationInfo ->
+ partition_eqn :: Maybe Id -> HsLit -> EquationInfo ->
(Maybe EquationInfo, Maybe EquationInfo)
- partition_eqn lit (EqnInfo (LitPat k _ : remaining_pats) match_result)
- | lit `eq_lit` k = (Just (EqnInfo remaining_pats match_result), Nothing)
- -- NB the pattern is stripped off thhe EquationInfo
+ partition_eqn Nothing lit (EqnInfo n ctx (LitPat k _ : remaining_pats) match_result)
+ | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats match_result), Nothing)
+ -- NB the pattern is stripped off the EquationInfo
- partition_eqn lit (EqnInfo (NPat k _ _ : remaining_pats) match_result)
- | lit `eq_lit` k = (Just (EqnInfo remaining_pats match_result), Nothing)
- -- NB the pattern is stripped off thhe EquationInfo
+ partition_eqn Nothing lit (EqnInfo n ctx (NPat k _ _ : remaining_pats) match_result)
+ | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats match_result), Nothing)
+ -- NB the pattern is stripped off the EquationInfo
+
+ partition_eqn (Just master_n) lit
+ (EqnInfo n ctx (NPlusKPat n' k _ _ _ : remaining_pats) match_result)
+ | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats new_match_result), Nothing)
+ -- NB the pattern is stripped off the EquationInfo
+ where
+ new_match_result | master_n == n' = match_result
+ | otherwise = mkCoLetsMatchResult
+ [NonRec n' (Var master_n)] match_result
- -- Wild-card patterns, which will only show up in the shadows, go into both groups
- partition_eqn lit eqn@(EqnInfo (WildPat _ : remaining_pats) match_result)
- = (Just (EqnInfo remaining_pats match_result), Just eqn)
+ -- Wild-card patterns, which will only show up in the shadows,
+ -- go into both groups
+ partition_eqn nPlusK lit
+ eqn@(EqnInfo n ctx (WildPat _ : remaining_pats) match_result)
+ = (Just (EqnInfo n ctx remaining_pats match_result), Just eqn)
-- Default case; not for this pattern
- partition_eqn lit eqn = (Nothing, Just eqn)
+ partition_eqn nPlusK lit eqn = (Nothing, Just eqn)
-- ToDo: meditate about this equality business...
projects / ghc-hetmet.git / blobdiff