2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section{Haskell abstract syntax definition}
6 This module glues together the pieces of the Haskell abstract syntax,
7 which is declared in the various \tr{Hs*} modules. This module,
8 therefore, is almost nothing but re-exporting.
12 -- NB: don't reexport HsCore
13 -- this module tells about "real Haskell"
25 collectStmtsBinders, collectStmtBinders,
26 collectHsBinders, collectLocatedHsBinders,
27 collectMonoBinders, collectLocatedMonoBinders,
28 collectSigTysFromHsBinds, collectSigTysFromMonoBinds
31 #include "HsVersions.h"
41 import BasicTypes ( Fixity, Version, NewOrData )
44 import Name ( NamedThing )
46 import SrcLoc ( SrcLoc )
47 import Module ( Module )
50 All we actually declare here is the top-level structure for a module.
54 (Maybe Module) -- Nothing => "module X where" is omitted
55 -- (in which case the next field is Nothing too)
56 (Maybe [IE name]) -- Export list; Nothing => export list omitted, so export everything
57 -- Just [] => export *nothing*
58 -- Just [...] => as you would expect...
59 [ImportDecl name] -- We snaffle interesting stuff out of the
60 -- imported interfaces early on, adding that
61 -- info to TyDecls/etc; so this list is
62 -- often empty, downstream.
63 [HsDecl name] -- Type, class, value, and interface signature decls
64 (Maybe DeprecTxt) -- reason/explanation for deprecation of this module
69 instance (NamedThing name, OutputableBndr name)
70 => Outputable (HsModule name) where
72 ppr (HsModule Nothing _ imports decls _ src_loc)
73 = pp_nonnull imports $$ pp_nonnull decls
75 ppr (HsModule (Just name) exports imports decls deprec src_loc)
78 Nothing -> pp_header (ptext SLIT("where"))
81 nest 8 (fsep (punctuate comma (map ppr es))),
82 nest 4 (ptext SLIT(") where"))
88 pp_header rest = case deprec of
89 Nothing -> pp_modname <+> rest
90 Just d -> vcat [ pp_modname, ppr d, rest ]
92 pp_modname = ptext SLIT("module") <+> ppr name
95 pp_nonnull xs = vcat (map ppr xs)
99 %************************************************************************
101 \subsection{Collecting binders from @HsBinds@}
103 %************************************************************************
105 Get all the binders in some @MonoBinds@, IN THE ORDER OF APPEARANCE.
107 These functions are here, rather than in HsBinds, to avoid a loop between HsPat and HsBinds.
116 it should return @[x, y, f, a, b]@ (remember, order important).
119 collectLocatedHsBinders :: HsBinds name -> [(name,SrcLoc)]
120 -- Used at top level only; so no need for an IPBinds case
121 collectLocatedHsBinders EmptyBinds = []
122 collectLocatedHsBinders (MonoBind b _ _)
123 = collectLocatedMonoBinders b
124 collectLocatedHsBinders (ThenBinds b1 b2)
125 = collectLocatedHsBinders b1 ++ collectLocatedHsBinders b2
127 collectHsBinders :: HsBinds name -> [name]
128 collectHsBinders EmptyBinds = []
129 collectHsBinders (IPBinds _ _) = [] -- Implicit parameters don't create
131 collectHsBinders (MonoBind b _ _) = collectMonoBinders b
132 collectHsBinders (ThenBinds b1 b2) = collectHsBinders b1 ++ collectHsBinders b2
134 collectLocatedMonoBinders :: MonoBinds name -> [(name,SrcLoc)]
135 collectLocatedMonoBinders binds
138 go EmptyMonoBinds acc = acc
139 go (PatMonoBind pat _ loc) acc = map (\v->(v,loc)) (collectPatBinders pat) ++ acc
140 go (FunMonoBind f _ _ loc) acc = (f,loc) : acc
141 go (AndMonoBinds bs1 bs2) acc = go bs1 (go bs2 acc)
143 collectMonoBinders :: MonoBinds name -> [name]
144 collectMonoBinders binds
147 go EmptyMonoBinds acc = acc
148 go (PatMonoBind pat _ loc) acc = collectPatBinders pat ++ acc
149 go (FunMonoBind f _ _ loc) acc = f : acc
150 go (AndMonoBinds bs1 bs2) acc = go bs1 (go bs2 acc)
151 go (VarMonoBind v _) acc = v : acc
152 go (AbsBinds _ _ dbinds _ binds) acc
153 = [dp | (_,dp,_) <- dbinds] ++ go binds acc
157 %************************************************************************
159 \subsection{Getting patterns out of bindings}
161 %************************************************************************
163 Get all the pattern type signatures out of a bunch of bindings
166 collectSigTysFromHsBinds :: HsBinds name -> [HsType name]
167 collectSigTysFromHsBinds EmptyBinds = []
168 collectSigTysFromHsBinds (IPBinds _ _) = []
169 collectSigTysFromHsBinds (MonoBind b _ _) = collectSigTysFromMonoBinds b
170 collectSigTysFromHsBinds (ThenBinds b1 b2) = collectSigTysFromHsBinds b1 ++
171 collectSigTysFromHsBinds b2
174 collectSigTysFromMonoBinds :: MonoBinds name -> [HsType name]
175 collectSigTysFromMonoBinds bind
178 go EmptyMonoBinds acc = acc
179 go (PatMonoBind pat _ loc) acc = collectSigTysFromPat pat ++ acc
180 go (FunMonoBind f _ ms loc) acc = go_matches ms acc
181 go (AndMonoBinds bs1 bs2) acc = go bs1 (go bs2 acc)
183 -- A binding like x :: a = f y
184 -- is parsed as FunMonoBind, but for this purpose we
185 -- want to treat it as a pattern binding
186 go_matches [] acc = acc
187 go_matches (Match [] (Just sig) _ : matches) acc = sig : go_matches matches acc
188 go_matches (match : matches) acc = go_matches matches acc
192 collectStmtsBinders :: [Stmt id] -> [id]
193 collectStmtsBinders = concatMap collectStmtBinders
195 collectStmtBinders :: Stmt id -> [id]
196 -- Id Binders for a Stmt... [but what about pattern-sig type vars]?
197 collectStmtBinders (BindStmt pat _ _) = collectPatBinders pat
198 collectStmtBinders (LetStmt binds) = collectHsBinders binds
199 collectStmtBinders (ExprStmt _ _ _) = []
200 collectStmtBinders (ResultStmt _ _) = []
201 collectStmtBinders (RecStmt ss _ _ _) = collectStmtsBinders ss
202 collectStmtBinders other = panic "collectStmtBinders"