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,
24 import IdInfo ( setArityInfo, vanillaIdInfo,
25 newStrictnessInfo, setAllStrictnessInfo,
26 newDemandInfo, setNewDemandInfo )
27 import Type ( tidyType, tidyTyVarBndr )
30 import Name ( getOccName )
31 import OccName ( tidyOccName )
32 import SrcLoc ( noSrcLoc )
33 import Maybes ( orElse )
35 import Util ( mapAccumL )
39 This module contains "tidying" code for *nested* expressions, bindings, rules.
40 The code for *top-level* bindings is in TidyPgm.
42 %************************************************************************
44 \subsection{Tidying expressions, rules}
46 %************************************************************************
51 -> (TidyEnv, CoreBind)
53 tidyBind env (NonRec bndr rhs)
54 = tidyLetBndr env (bndr,rhs) =: \ (env', bndr') ->
55 (env', NonRec bndr' (tidyExpr env' rhs))
57 tidyBind env (Rec prs)
58 = mapAccumL tidyLetBndr env prs =: \ (env', bndrs') ->
59 map (tidyExpr env') (map snd prs) =: \ rhss' ->
60 (env', Rec (zip bndrs' rhss'))
63 ------------ Expressions --------------
64 tidyExpr :: TidyEnv -> CoreExpr -> CoreExpr
65 tidyExpr env (Var v) = Var (tidyVarOcc env v)
66 tidyExpr env (Type ty) = Type (tidyType env ty)
67 tidyExpr env (Lit lit) = Lit lit
68 tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
69 tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
71 tidyExpr env (Let b e)
72 = tidyBind env b =: \ (env', b') ->
73 Let b' (tidyExpr env' e)
75 tidyExpr env (Case e b alts)
76 = tidyBndr env b =: \ (env', b) ->
77 Case (tidyExpr env e) b (map (tidyAlt env') alts)
79 tidyExpr env (Lam b e)
80 = tidyBndr env b =: \ (env', b) ->
81 Lam b (tidyExpr env' e)
83 ------------ Case alternatives --------------
84 tidyAlt env (con, vs, rhs)
85 = tidyBndrs env vs =: \ (env', vs) ->
86 (con, vs, tidyExpr env' rhs)
88 ------------ Notes --------------
89 tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
90 tidyNote env note = note
93 ------------ Rules --------------
94 tidyIdRules :: TidyEnv -> [IdCoreRule] -> [IdCoreRule]
95 tidyIdRules env [] = []
96 tidyIdRules env ((fn,rule) : rules)
97 = tidyRule env rule =: \ rule ->
98 tidyIdRules env rules =: \ rules ->
99 ((tidyVarOcc env fn, rule) : rules)
101 tidyRule :: TidyEnv -> CoreRule -> CoreRule
102 tidyRule env rule@(BuiltinRule _ _) = rule
103 tidyRule env (Rule name act vars tpl_args rhs)
104 = tidyBndrs env vars =: \ (env', vars) ->
105 map (tidyExpr env') tpl_args =: \ tpl_args ->
106 (Rule name act vars tpl_args (tidyExpr env' rhs))
108 pprTidyIdRules :: Id -> SDoc
109 pprTidyIdRules id = pprIdRules (tidyIdRules emptyTidyEnv (idCoreRules id))
113 %************************************************************************
115 \subsection{Tidying non-top-level binders}
117 %************************************************************************
120 tidyVarOcc :: TidyEnv -> Var -> Var
121 tidyVarOcc (_, var_env) v = lookupVarEnv var_env v `orElse` v
123 -- tidyBndr is used for lambda and case binders
124 tidyBndr :: TidyEnv -> Var -> (TidyEnv, Var)
126 | isTyVar var = tidyTyVarBndr env var
127 | otherwise = tidyIdBndr env var
129 tidyBndrs :: TidyEnv -> [Var] -> (TidyEnv, [Var])
130 tidyBndrs env vars = mapAccumL tidyBndr env vars
132 tidyLetBndr :: TidyEnv -> (Id, CoreExpr) -> (TidyEnv, Var)
133 -- Used for local (non-top-level) let(rec)s
134 tidyLetBndr env (id,rhs)
135 = ((tidy_env,new_var_env), final_id)
137 ((tidy_env,var_env), new_id) = tidyIdBndr env id
139 -- We need to keep around any interesting strictness and
140 -- demand info because later on we may need to use it when
141 -- converting to A-normal form.
143 -- f (g x), where f is strict in its argument, will be converted
144 -- into case (g x) of z -> f z by CorePrep, but only if f still
145 -- has its strictness info.
147 -- Similarly for the demand info - on a let binder, this tells
148 -- CorePrep to turn the let into a case.
150 -- Similarly arity info for eta expansion in CorePrep
152 final_id = new_id `setIdInfo` new_info
154 new_info = vanillaIdInfo
155 `setArityInfo` exprArity rhs
156 `setAllStrictnessInfo` newStrictnessInfo idinfo
157 `setNewDemandInfo` newDemandInfo idinfo
159 -- Override the env we get back from tidyId with the new IdInfo
160 -- so it gets propagated to the usage sites.
161 new_var_env = extendVarEnv var_env id final_id
163 -- Non-top-level variables
164 tidyIdBndr :: TidyEnv -> Id -> (TidyEnv, Id)
165 tidyIdBndr env@(tidy_env, var_env) id
166 = -- do this pattern match strictly, otherwise we end up holding on to
167 -- stuff in the OccName.
168 case tidyOccName tidy_env (getOccName id) of { (tidy_env', occ') ->
170 -- Give the Id a fresh print-name, *and* rename its type
171 -- The SrcLoc isn't important now,
172 -- though we could extract it from the Id
174 -- All nested Ids now have the same IdInfo, namely vanillaIdInfo,
175 -- which should save some space.
176 -- But note that tidyLetBndr puts some of it back.
177 ty' = tidyType env (idType id)
178 id' = mkUserLocal occ' (idUnique id) ty' noSrcLoc
179 `setIdInfo` vanillaIdInfo
180 var_env' = extendVarEnv var_env id id'
182 ((tidy_env', var_env'), id')