\section[MatchLit]{Pattern-matching literal patterns}
\begin{code}
-module MatchLit ( matchLiterals ) where
+module MatchLit ( dsLit, matchLiterals ) where
#include "HsVersions.h"
import {-# SOURCE #-} Match ( match )
import {-# SOURCE #-} DsExpr ( dsExpr )
-import HsSyn ( HsLit(..), OutPat(..), HsExpr(..) )
-import TcHsSyn ( TypecheckedPat )
-import CoreSyn ( Expr(..), Bind(..) )
-import Id ( Id )
-
import DsMonad
+import DsCCall ( resultWrapper )
import DsUtils
+import HsSyn ( HsLit(..), Pat(..), HsExpr(..) )
+import TcHsSyn ( TypecheckedPat )
+import Id ( Id )
+import CoreSyn
+import TyCon ( tyConDataCons )
+import TcType ( tcSplitTyConApp, isIntegerTy )
+
+import PrelNames ( ratioTyConKey )
+import Unique ( hasKey )
import Literal ( mkMachInt, Literal(..) )
import Maybes ( catMaybes )
import Type ( isUnLiftedType )
import Panic ( panic, assertPanic )
+import Maybe ( isJust )
+import Ratio ( numerator, denominator )
\end{code}
+%************************************************************************
+%* *
+ Desugaring literals
+ [used to be in DsExpr, but DsMeta needs it,
+ and it's nice to avoid a loop]
+%* *
+%************************************************************************
+
+We give int/float literals type @Integer@ and @Rational@, respectively.
+The typechecker will (presumably) have put \tr{from{Integer,Rational}s}
+around them.
+
+ToDo: put in range checks for when converting ``@i@''
+(or should that be in the typechecker?)
+
+For numeric literals, we try to detect there use at a standard type
+(@Int@, @Float@, etc.) are directly put in the right constructor.
+[NB: down with the @App@ conversion.]
+
+See also below where we look for @DictApps@ for \tr{plusInt}, etc.
+
+\begin{code}
+dsLit :: HsLit -> DsM CoreExpr
+dsLit (HsChar c) = returnDs (mkCharExpr c)
+dsLit (HsCharPrim c) = returnDs (mkLit (MachChar c))
+dsLit (HsString str) = mkStringLitFS str
+dsLit (HsStringPrim s) = returnDs (mkLit (MachStr s))
+dsLit (HsInteger i) = mkIntegerExpr i
+dsLit (HsInt i) = returnDs (mkIntExpr i)
+dsLit (HsIntPrim i) = returnDs (mkIntLit i)
+dsLit (HsFloatPrim f) = returnDs (mkLit (MachFloat f))
+dsLit (HsDoublePrim d) = returnDs (mkLit (MachDouble d))
+dsLit (HsLitLit str ty)
+ = ASSERT( isJust maybe_ty )
+ returnDs (wrap_fn (mkLit (MachLitLit str rep_ty)))
+ where
+ (maybe_ty, wrap_fn) = resultWrapper ty
+ Just rep_ty = maybe_ty
+
+dsLit (HsRat r ty)
+ = mkIntegerExpr (numerator r) `thenDs` \ num ->
+ mkIntegerExpr (denominator r) `thenDs` \ denom ->
+ returnDs (mkConApp ratio_data_con [Type integer_ty, num, denom])
+ where
+ (ratio_data_con, integer_ty)
+ = case tcSplitTyConApp ty of
+ (tycon, [i_ty]) -> ASSERT(isIntegerTy i_ty && tycon `hasKey` ratioTyConKey)
+ (head (tyConDataCons tycon), i_ty)
+\end{code}
+
+%************************************************************************
+%* *
+ Pattern matching on literals
+%* *
+%************************************************************************
+
\begin{code}
matchLiterals :: [Id]
-> [EquationInfo]
the alts---here we use @match_prims_used@.
\begin{code}
-matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal lit_ty : ps1) _ : eqns)
+matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal : ps1) _ : eqns)
= -- GENERATE THE ALTS
match_prims_used vars eqns_info `thenDs` \ prim_alts ->
where
match_prims_used _ [{-no more eqns-}] = returnDs []
- match_prims_used vars eqns_info@(EqnInfo n ctx (pat@(LitPat literal lit_ty):ps1) _ : eqns)
+ match_prims_used vars eqns_info@(EqnInfo n ctx (pat@(LitPat literal):ps1) _ : eqns)
= let
(shifted_eqns_for_this_lit, eqns_not_for_this_lit)
= partitionEqnsByLit pat eqns_info
\begin{code}
matchLiterals all_vars@(var:vars)
- eqns_info@(EqnInfo n ctx (pat@(NPat literal lit_ty eq_chk):ps1) _ : eqns)
+ eqns_info@(EqnInfo n ctx (pat@(NPatOut literal lit_ty eq_chk):ps1) _ : eqns)
= let
(shifted_eqns_for_this_lit, eqns_not_for_this_lit)
= partitionEqnsByLit pat eqns_info
\begin{code}
-matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (pat@(NPlusKPat master_n k ty ge sub):ps1) _ : eqns)
+matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (pat@(NPlusKPatOut master_n k ge sub):ps1) _ : eqns)
= let
(shifted_eqns_for_this_lit, eqns_not_for_this_lit)
= partitionEqnsByLit pat eqns_info
where
partition_eqn :: TypecheckedPat -> EquationInfo -> (Maybe EquationInfo, Maybe EquationInfo)
- partition_eqn (LitPat k1 _) (EqnInfo n ctx (LitPat k2 _ : remaining_pats) match_result)
+ partition_eqn (LitPat k1) (EqnInfo n ctx (LitPat k2 : remaining_pats) match_result)
| k1 == k2 = (Just (EqnInfo n ctx remaining_pats match_result), Nothing)
-- NB the pattern is stripped off the EquationInfo
- partition_eqn (NPat k1 _ _) (EqnInfo n ctx (NPat k2 _ _ : remaining_pats) match_result)
+ partition_eqn (NPatOut k1 _ _) (EqnInfo n ctx (NPatOut k2 _ _ : remaining_pats) match_result)
| k1 == k2 = (Just (EqnInfo n ctx remaining_pats match_result), Nothing)
-- NB the pattern is stripped off the EquationInfo
- partition_eqn (NPlusKPat master_n k1 _ _ _)
- (EqnInfo n ctx (NPlusKPat n' k2 _ _ _ : remaining_pats) match_result)
+ partition_eqn (NPlusKPatOut master_n k1 _ _)
+ (EqnInfo n ctx (NPlusKPatOut n' k2 _ _ : remaining_pats) match_result)
| k1 == k2 = (Just (EqnInfo n ctx remaining_pats new_match_result), Nothing)
-- NB the pattern is stripped off the EquationInfo
where
-- Default case; not for this pattern
partition_eqn master_pat eqn = (Nothing, Just eqn)
\end{code}
+
projects / ghc-hetmet.git / blobdiff