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.
9 #include "HsVersions.h"
24 import PrefixSyn -- and various syntaxen.
27 import HsPragmas ( noGenPragmas, noClassOpPragmas )
29 import SrcLoc ( mkSrcLoc )
30 import Util ( mapAndUnzip, panic, assertPanic )
33 %************************************************************************
35 \subsection[cvDecls]{Convert various top-level declarations}
37 %************************************************************************
39 We make a point not to throw any user-pragma ``sigs'' at
40 these conversion functions:
42 cvValSig, cvClassOpSig, cvInstDeclSig :: SigConverter
44 cvValSig (RdrTySig vars poly_ty src_loc)
45 = [ Sig v poly_ty src_loc | v <- vars ]
47 cvClassOpSig (RdrTySig vars poly_ty src_loc)
48 = [ ClassOpSig v Nothing poly_ty src_loc | v <- vars ]
50 cvInstDeclSig (RdrSpecValSig sigs) = sigs
51 cvInstDeclSig (RdrInlineValSig sig) = [ sig ]
52 cvInstDeclSig (RdrDeforestSig sig) = [ sig ]
53 cvInstDeclSig (RdrMagicUnfoldingSig sig) = [ sig ]
56 %************************************************************************
58 \subsection[cvBinds-etc]{Converting to @HsBinds@, @MonoBinds@, etc.}
60 %************************************************************************
62 Function definitions are restructured here. Each is assumed to be recursive
63 initially, and non recursive definitions are discovered by the dependency
67 cvBinds :: SrcFile -> SigConverter -> RdrBinding -> RdrNameHsBinds
68 cvBinds sf sig_cvtr binding
69 = case (cvMonoBindsAndSigs sf sig_cvtr binding) of { (mbs, sigs) ->
70 MonoBind mbs sigs recursive
75 cvMonoBindsAndSigs :: SrcFile
78 -> (RdrNameMonoBinds, [RdrNameSig])
80 cvMonoBindsAndSigs sf sig_cvtr fb
81 = mangle_bind (EmptyMonoBinds, []) fb
83 -- If the function being bound has at least one argument, then the
84 -- guarded right hand sides of each pattern binding are knitted
85 -- into a series of patterns, each matched with its corresponding
86 -- guarded right hand side (which may contain several
87 -- alternatives). This series is then paired with the name of the
88 -- function. Otherwise there is only one pattern, which is paired
89 -- with a guarded right hand side.
91 mangle_bind acc (RdrAndBindings fb1 fb2)
92 = mangle_bind (mangle_bind acc fb1) fb2
94 mangle_bind (b_acc, s_acc) sig@(RdrTySig _ _ _)
95 = (b_acc, s_acc ++ sig_cvtr sig)
97 mangle_bind (b_acc, s_acc) (RdrSpecValSig sig) = (b_acc, sig ++ s_acc)
98 mangle_bind (b_acc, s_acc) (RdrInlineValSig sig) = (b_acc, sig : s_acc)
99 mangle_bind (b_acc, s_acc) (RdrDeforestSig sig) = (b_acc, sig : s_acc)
100 mangle_bind (b_acc, s_acc) (RdrMagicUnfoldingSig sig) = (b_acc, sig : s_acc)
102 mangle_bind (b_acc, s_acc)
103 (RdrPatternBinding lousy_srcline [patbinding])
104 -- WDP: the parser has trouble getting a good line-number on RdrPatternBindings.
105 = case (cvPatMonoBind sf patbinding) of { (pat, grhss, binds) ->
107 src_loc = mkSrcLoc sf good_srcline
109 (b_acc `AndMonoBinds`
110 PatMonoBind pat (GRHSsAndBindsIn grhss binds) src_loc, s_acc)
113 good_srcline = case patbinding of
114 RdrMatch_NoGuard ln _ _ _ _ -> ln
115 RdrMatch_Guards ln _ _ _ _ -> ln
118 mangle_bind _ (RdrPatternBinding _ _)
119 = panic "mangleBinding: more than one pattern on a RdrPatternBinding"
121 mangle_bind (b_acc, s_acc) (RdrFunctionBinding srcline patbindings)
122 -- must be a function binding...
123 = case (cvFunMonoBind sf patbindings) of { (var, inf, matches) ->
124 (b_acc `AndMonoBinds`
125 FunMonoBind var inf matches (mkSrcLoc sf srcline), s_acc)
128 mangle_bind (b_acc, s_acc) other = (b_acc, s_acc)
132 cvPatMonoBind :: SrcFile -> RdrMatch -> (RdrNamePat, [RdrNameGRHS], RdrNameHsBinds)
134 cvPatMonoBind sf (RdrMatch_NoGuard srcline srcfun pat expr binding)
135 = (pat, [OtherwiseGRHS expr (mkSrcLoc sf srcline)], cvBinds sf cvValSig binding)
137 cvPatMonoBind sf (RdrMatch_Guards srcline srcfun pat guardedexprs binding)
138 = (pat, map (cvGRHS sf srcline) guardedexprs, cvBinds sf cvValSig binding)
140 cvFunMonoBind :: SrcFile -> [RdrMatch] -> (RdrName {-VarName-}, Bool {-InfixDefn-}, [RdrNameMatch])
142 cvFunMonoBind sf matches
143 = (head srcfuns, head infixdefs, cvMatches sf False matches)
145 (srcfuns, infixdefs) = mapAndUnzip get_mdef matches
146 -- ToDo: Check for consistent srcfun and infixdef
148 get_mdef (RdrMatch_NoGuard _ sfun pat _ _) = get_pdef pat
149 get_mdef (RdrMatch_Guards _ sfun pat _ _) = get_pdef pat
151 get_pdef (ConPatIn fn _) = (fn, False)
152 get_pdef (ConOpPatIn _ op _ _) = (op, True)
153 get_pdef (ParPatIn pat) = get_pdef pat
156 cvMatches :: SrcFile -> Bool -> [RdrMatch] -> [RdrNameMatch]
157 cvMatch :: SrcFile -> Bool -> RdrMatch -> RdrNameMatch
159 cvMatches sf is_case matches = map (cvMatch sf is_case) matches
161 cvMatch sf is_case rdr_match
163 (GRHSMatch (GRHSsAndBindsIn guarded_exprs (cvBinds sf cvValSig binding)))
165 -- For a FunMonoBinds, the first flattened "pattern" is
166 -- just the function name, and we don't want to keep it.
167 -- For a case expr, it's (presumably) a constructor name -- and
168 -- we most certainly want to keep it! Hence the monkey busines...
170 (if is_case then -- just one pattern: leave it untouched...
172 else -- function pattern; extract arg patterns...
173 case pat of ConPatIn fn pats -> pats
174 ConOpPatIn p1 op _ p2 -> [p1,p2]
175 ParPatIn pat -> panic "PrefixToHs.cvMatch:ParPatIn"
178 (pat, binding, guarded_exprs)
180 RdrMatch_NoGuard ln b c expr d -> (c,d, [OtherwiseGRHS expr (mkSrcLoc sf ln)])
181 RdrMatch_Guards ln b c gd_exps d -> (c,d, map (cvGRHS sf ln) gd_exps)
183 cvGRHS :: SrcFile -> SrcLine -> ([RdrNameStmt], RdrNameHsExpr) -> RdrNameGRHS
184 cvGRHS sf sl (g, e) = GRHS g e (mkSrcLoc sf sl)
187 %************************************************************************
189 \subsection[PrefixToHS-utils]{Utilities for conversion}
191 %************************************************************************
193 Separate declarations into all the various kinds:
196 cvOtherDecls :: RdrBinding -> [RdrNameHsDecl]
200 go acc (RdrAndBindings b1 b2) = go (go acc b1) b2
201 go acc (RdrTyDecl d) = TyD d : acc
202 go acc (RdrClassDecl d) = ClD d : acc
203 go acc (RdrInstDecl d) = InstD d : acc
204 go acc (RdrDefaultDecl d) = DefD d : acc