2 % (c) The AQUA Project, Glasgow University, 1996-1998
4 %************************************************************************
6 \section[PprCore]{Printing of Core syntax, including for interfaces}
8 %************************************************************************
13 tidyBndr, tidyBndrs, tidyVarOcc,
14 tidyIdRules, pprTidyIdRules
17 #include "HsVersions.h"
20 import CoreUtils ( exprArity )
21 import PprCore ( pprIdRules )
22 import Id ( Id, mkUserLocal, idInfo, setIdInfo, idUnique, idType, idCoreRules )
23 import IdInfo ( vanillaIdInfo, setArityInfo,
24 newStrictnessInfo, setAllStrictnessInfo,
25 newDemandInfo, setNewDemandInfo )
26 import Type ( tidyType, tidyTyVarBndr )
29 import Name ( getOccName )
30 import OccName ( tidyOccName )
31 import SrcLoc ( noSrcLoc )
32 import Maybes ( orElse )
34 import Util ( mapAccumL )
38 %************************************************************************
40 \subsection{Tidying expressions, rules}
42 %************************************************************************
47 -> (TidyEnv, CoreBind)
49 tidyBind env (NonRec bndr rhs)
50 = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') ->
51 (env', NonRec bndr' (tidyExpr env' rhs))
53 tidyBind env (Rec prs)
54 = mapAccumL tidyLetBndr env prs =: \ (env', bndrs') ->
55 map (tidyExpr env') (map snd prs) =: \ rhss' ->
56 (env', Rec (zip bndrs' rhss'))
59 ------------ Expressions --------------
60 tidyCoreExpr :: CoreExpr -> IO CoreExpr
61 tidyCoreExpr expr = return (tidyExpr emptyTidyEnv expr)
63 tidyExpr env (Var v) = Var (tidyVarOcc env v)
64 tidyExpr env (Type ty) = Type (tidyType env ty)
65 tidyExpr env (Lit lit) = Lit lit
66 tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
67 tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
69 tidyExpr env (Let b e)
70 = tidyBind env b =: \ (env', b') ->
71 Let b' (tidyExpr env' e)
73 tidyExpr env (Case e b alts)
74 = tidyBndr env b =: \ (env', b) ->
75 Case (tidyExpr env e) b (map (tidyAlt env') alts)
77 tidyExpr env (Lam b e)
78 = tidyBndr env b =: \ (env', b) ->
79 Lam b (tidyExpr env' e)
81 ------------ Case alternatives --------------
82 tidyAlt env (con, vs, rhs)
83 = tidyBndrs env vs =: \ (env', vs) ->
84 (con, vs, tidyExpr env' rhs)
86 ------------ Notes --------------
87 tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
88 tidyNote env note = note
91 ------------ Rules --------------
92 tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule]
93 tidyIdRules env [] = []
94 tidyIdRules env ((fn,rule) : rules)
95 = tidyRule env rule =: \ rule ->
96 tidyIdRules env rules =: \ rules ->
97 ((tidyVarOcc env fn, rule) : rules)
99 tidyRule :: TidyEnv -> CoreRule -> CoreRule
100 tidyRule env rule@(BuiltinRule _ _) = rule
101 tidyRule env (Rule name act vars tpl_args rhs)
102 = tidyBndrs env vars =: \ (env', vars) ->
103 map (tidyExpr env') tpl_args =: \ tpl_args ->
104 (Rule name act vars tpl_args (tidyExpr env' rhs))
106 pprTidyIdRules :: Id -> SDoc
107 pprTidyIdRules id = pprIdRules (tidyIdRules emptyTidyEnv (idCoreRules id))
111 %************************************************************************
113 \subsection{Tidying non-top-level binders}
115 %************************************************************************
118 tidyVarOcc :: TidyEnv -> Var -> Var
119 tidyVarOcc (_, var_env) v = lookupVarEnv var_env v `orElse` v
121 -- tidyBndr is used for lambda and case binders
122 tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
124 | isTyVar var = tidyTyVarBndr env var
125 | otherwise = tidyIdBndr env var
127 tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
128 tidyBndrs env vars = mapAccumL tidyBndr env vars
130 tidyLetBndr :: TidyEnv -> (Id, CoreExpr) -> (TidyEnv, Var)
131 -- Used for local (non-top-level) let(rec)s
132 tidyLetBndr env (id,rhs)
133 = ((tidy_env,new_var_env), final_id)
135 ((tidy_env,var_env), new_id) = tidyIdBndr env id
137 -- We need to keep around any interesting strictness and demand info
138 -- because later on we may need to use it when converting to A-normal form.
140 -- f (g x), where f is strict in its argument, will be converted
141 -- into case (g x) of z -> f z by CorePrep, but only if f still
142 -- has its strictness info.
144 -- Similarly for the demand info - on a let binder, this tells
145 -- CorePrep to turn the let into a case.
147 -- Similarly arity info for eta expansion in CorePrep
148 final_id = new_id `setIdInfo` new_info
150 new_info = vanillaIdInfo
151 `setArityInfo` exprArity rhs
152 `setAllStrictnessInfo` newStrictnessInfo idinfo
153 `setNewDemandInfo` newDemandInfo idinfo
155 -- Override the env we get back from tidyId with the new IdInfo
156 -- so it gets propagated to the usage sites.
157 new_var_env = extendVarEnv var_env id final_id
159 -- Non-top-level variables
160 tidyIdBndr :: TidyEnv -> Id -> (TidyEnv, Id)
161 tidyIdBndr env@(tidy_env, var_env) id
162 = -- do this pattern match strictly, otherwise we end up holding on to
163 -- stuff in the OccName.
164 case tidyOccName tidy_env (getOccName id) of { (tidy_env', occ') ->
166 -- Give the Id a fresh print-name, *and* rename its type
167 -- The SrcLoc isn't important now,
168 -- though we could extract it from the Id
170 -- All nested Ids now have the same IdInfo, namely none,
171 -- which should save some space.
172 -- But note that tidyLetBndr puts some of it back.
173 ty' = tidyType env (idType id)
174 id' = mkUserLocal occ' (idUnique id) ty' noSrcLoc
175 var_env' = extendVarEnv var_env id id'
177 ((tidy_env', var_env'), id')