2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
4 \section[PrefixToHS]{Support routines for converting ``prefix form'' to Haskell abstract syntax}
6 Support routines for reading prefix-form from the Lex/Yacc parser.
20 #include "HsVersions.h"
22 import PrefixSyn -- and various syntaxen.
25 import HsPragmas ( noGenPragmas, noClassOpPragmas )
27 import BasicTypes ( RecFlag(..) )
28 import SrcLoc ( mkSrcLoc )
29 import Util ( mapAndUnzip, panic, assertPanic )
32 %************************************************************************
34 \subsection[cvDecls]{Convert various top-level declarations}
36 %************************************************************************
38 We make a point not to throw any user-pragma ``sigs'' at
39 these conversion functions:
41 cvValSig, cvClassOpSig, cvInstDeclSig :: SigConverter
43 cvValSig (RdrTySig vars poly_ty src_loc)
44 = [ Sig v poly_ty src_loc | v <- vars ]
46 cvClassOpSig (RdrTySig vars poly_ty src_loc)
47 = [ ClassOpSig v Nothing poly_ty src_loc | v <- vars ]
49 cvInstDeclSig (RdrSpecValSig sigs) = sigs
50 cvInstDeclSig (RdrInlineValSig sig) = [ sig ]
51 cvInstDeclSig (RdrMagicUnfoldingSig sig) = [ sig ]
54 %************************************************************************
56 \subsection[cvBinds-etc]{Converting to @HsBinds@, @MonoBinds@, etc.}
58 %************************************************************************
60 Function definitions are restructured here. Each is assumed to be recursive
61 initially, and non recursive definitions are discovered by the dependency
65 cvBinds :: SrcFile -> SigConverter -> RdrBinding -> RdrNameHsBinds
66 cvBinds sf sig_cvtr binding
67 = case (cvMonoBindsAndSigs sf sig_cvtr binding) of { (mbs, sigs) ->
68 MonoBind mbs sigs Recursive
73 cvMonoBindsAndSigs :: SrcFile
76 -> (RdrNameMonoBinds, [RdrNameSig])
78 cvMonoBindsAndSigs sf sig_cvtr fb
79 = mangle_bind (EmptyMonoBinds, []) fb
81 -- If the function being bound has at least one argument, then the
82 -- guarded right hand sides of each pattern binding are knitted
83 -- into a series of patterns, each matched with its corresponding
84 -- guarded right hand side (which may contain several
85 -- alternatives). This series is then paired with the name of the
86 -- function. Otherwise there is only one pattern, which is paired
87 -- with a guarded right hand side.
89 mangle_bind acc (RdrAndBindings fb1 fb2)
90 = mangle_bind (mangle_bind acc fb1) fb2
92 mangle_bind (b_acc, s_acc) sig@(RdrTySig _ _ _)
93 = (b_acc, s_acc ++ sig_cvtr sig)
95 mangle_bind (b_acc, s_acc) (RdrSpecValSig sig) = (b_acc, sig ++ s_acc)
96 mangle_bind (b_acc, s_acc) (RdrInlineValSig sig) = (b_acc, sig : s_acc)
97 mangle_bind (b_acc, s_acc) (RdrMagicUnfoldingSig sig) = (b_acc, sig : s_acc)
99 mangle_bind (b_acc, s_acc)
100 (RdrPatternBinding lousy_srcline [patbinding])
101 -- WDP: the parser has trouble getting a good line-number on RdrPatternBindings.
102 = case (cvPatMonoBind sf patbinding) of { (pat, grhss, binds) ->
104 src_loc = mkSrcLoc sf good_srcline
106 (b_acc `AndMonoBinds`
107 PatMonoBind pat (GRHSsAndBindsIn grhss binds) src_loc, s_acc)
110 good_srcline = case patbinding of
111 RdrMatch_NoGuard ln _ _ _ _ -> ln
112 RdrMatch_Guards ln _ _ _ _ -> ln
115 mangle_bind _ (RdrPatternBinding _ _)
116 = panic "mangleBinding: more than one pattern on a RdrPatternBinding"
118 mangle_bind (b_acc, s_acc) (RdrFunctionBinding srcline patbindings)
119 -- must be a function binding...
120 = case (cvFunMonoBind sf patbindings) of { (var, inf, matches) ->
121 (b_acc `AndMonoBinds`
122 FunMonoBind var inf matches (mkSrcLoc sf srcline), s_acc)
125 mangle_bind (b_acc, s_acc) other = (b_acc, s_acc)
129 cvPatMonoBind :: SrcFile -> RdrMatch -> (RdrNamePat, [RdrNameGRHS], RdrNameHsBinds)
131 cvPatMonoBind sf (RdrMatch_NoGuard srcline srcfun pat expr binding)
132 = (pat, unguardedRHS expr (mkSrcLoc sf srcline), cvBinds sf cvValSig binding)
134 cvPatMonoBind sf (RdrMatch_Guards srcline srcfun pat guardedexprs binding)
135 = (pat, map (cvGRHS sf srcline) guardedexprs, cvBinds sf cvValSig binding)
137 cvFunMonoBind :: SrcFile -> [RdrMatch] -> (RdrName {-VarName-}, Bool {-InfixDefn-}, [RdrNameMatch])
139 cvFunMonoBind sf matches
140 = (head srcfuns, head infixdefs, cvMatches sf False matches)
142 (srcfuns, infixdefs) = mapAndUnzip get_mdef matches
143 -- ToDo: Check for consistent srcfun and infixdef
145 get_mdef (RdrMatch_NoGuard _ sfun pat _ _) = get_pdef pat
146 get_mdef (RdrMatch_Guards _ sfun pat _ _) = get_pdef pat
148 get_pdef (ConPatIn fn _) = (fn, False)
149 get_pdef (ConOpPatIn _ op _ _) = (op, True)
150 get_pdef (ParPatIn pat) = get_pdef pat
153 cvMatches :: SrcFile -> Bool -> [RdrMatch] -> [RdrNameMatch]
154 cvMatch :: SrcFile -> Bool -> RdrMatch -> RdrNameMatch
156 cvMatches sf is_case matches = map (cvMatch sf is_case) matches
158 cvMatch sf is_case rdr_match
160 (GRHSMatch (GRHSsAndBindsIn guarded_exprs (cvBinds sf cvValSig binding)))
162 -- For a FunMonoBinds, the first flattened "pattern" is
163 -- just the function name, and we don't want to keep it.
164 -- For a case expr, it's (presumably) a constructor name -- and
165 -- we most certainly want to keep it! Hence the monkey busines...
167 (if is_case then -- just one pattern: leave it untouched...
169 else -- function pattern; extract arg patterns...
170 case pat of ConPatIn fn pats -> pats
171 ConOpPatIn p1 op _ p2 -> [p1,p2]
172 ParPatIn pat -> panic "PrefixToHs.cvMatch:ParPatIn"
175 (pat, binding, guarded_exprs)
177 RdrMatch_NoGuard ln b c expr d -> (c,d, unguardedRHS expr (mkSrcLoc sf ln))
178 RdrMatch_Guards ln b c gd_exps d -> (c,d, map (cvGRHS sf ln) gd_exps)
180 cvGRHS :: SrcFile -> SrcLine -> ([RdrNameStmt], RdrNameHsExpr) -> RdrNameGRHS
181 cvGRHS sf sl (g, e) = GRHS g e (mkSrcLoc sf sl)
184 %************************************************************************
186 \subsection[PrefixToHS-utils]{Utilities for conversion}
188 %************************************************************************
190 Separate declarations into all the various kinds:
193 cvOtherDecls :: RdrBinding -> [RdrNameHsDecl]
197 go acc (RdrAndBindings b1 b2) = go (go acc b1) b2
198 go acc (RdrTyDecl d) = TyD d : acc
199 go acc (RdrClassDecl d) = ClD d : acc
200 go acc (RdrInstDecl d) = InstD d : acc
201 go acc (RdrDefaultDecl d) = DefD d : acc