| ghc-6.10.4: The GHC API | Contents | Index

VarEnv

Contents

Var, Id and TyVar environments (maps)
  Manipulating these environments
The InScopeSet type
  Operations on InScopeSets
The RnEnv2 type
  Operations on RnEnv2s
TidyEnv and its operation

Synopsis

type VarEnv elt = UniqFM elt
type IdEnv elt = VarEnv elt
type TyVarEnv elt = VarEnv elt
emptyVarEnv :: VarEnv a
unitVarEnv :: Var -> a -> VarEnv a
mkVarEnv :: [(Var, a)] -> VarEnv a
elemVarEnv :: Var -> VarEnv a -> Bool
varEnvElts :: VarEnv a -> [a]
varEnvKeys :: VarEnv a -> [Unique]
extendVarEnv :: VarEnv a -> Var -> a -> VarEnv a
extendVarEnv_C :: (a -> a -> a) -> VarEnv a -> Var -> a -> VarEnv a
extendVarEnvList :: VarEnv a -> [(Var, a)] -> VarEnv a
plusVarEnv :: VarEnv a -> VarEnv a -> VarEnv a
plusVarEnv_C :: (a -> a -> a) -> VarEnv a -> VarEnv a -> VarEnv a
delVarEnvList :: VarEnv a -> [Var] -> VarEnv a
delVarEnv :: VarEnv a -> Var -> VarEnv a
lookupVarEnv :: VarEnv a -> Var -> Maybe a
lookupVarEnv_NF :: VarEnv a -> Var -> a
lookupWithDefaultVarEnv :: VarEnv a -> a -> Var -> a
mapVarEnv :: (a -> b) -> VarEnv a -> VarEnv b
zipVarEnv :: [Var] -> [a] -> VarEnv a
modifyVarEnv :: (a -> a) -> VarEnv a -> Var -> VarEnv a
modifyVarEnv_Directly :: (a -> a) -> UniqFM a -> Unique -> UniqFM a
isEmptyVarEnv :: VarEnv a -> Bool
foldVarEnv :: (a -> b -> b) -> b -> VarEnv a -> b
elemVarEnvByKey :: Unique -> VarEnv a -> Bool
lookupVarEnv_Directly :: VarEnv a -> Unique -> Maybe a
filterVarEnv_Directly :: (Unique -> a -> Bool) -> VarEnv a -> VarEnv a
data InScopeSet
emptyInScopeSet :: InScopeSet
mkInScopeSet :: VarEnv Var -> InScopeSet
delInScopeSet :: InScopeSet -> Var -> InScopeSet
extendInScopeSet :: InScopeSet -> Var -> InScopeSet
extendInScopeSetList :: InScopeSet -> [Var] -> InScopeSet
extendInScopeSetSet :: InScopeSet -> VarEnv Var -> InScopeSet
modifyInScopeSet :: InScopeSet -> Var -> Var -> InScopeSet
getInScopeVars :: InScopeSet -> VarEnv Var
lookupInScope :: InScopeSet -> Var -> Maybe Var
elemInScopeSet :: Var -> InScopeSet -> Bool
uniqAway :: InScopeSet -> Var -> Var
data RnEnv2
mkRnEnv2 :: InScopeSet -> RnEnv2
rnBndr2 :: RnEnv2 -> Var -> Var -> RnEnv2
rnBndrs2 :: RnEnv2 -> [Var] -> [Var] -> RnEnv2
rnOccL :: RnEnv2 -> Var -> Var
rnOccR :: RnEnv2 -> Var -> Var
inRnEnvL :: RnEnv2 -> Var -> Bool
inRnEnvR :: RnEnv2 -> Var -> Bool
rnBndrL :: RnEnv2 -> Var -> (RnEnv2, Var)
rnBndrR :: RnEnv2 -> Var -> (RnEnv2, Var)
nukeRnEnvL :: RnEnv2 -> RnEnv2
nukeRnEnvR :: RnEnv2 -> RnEnv2
extendRnInScopeList :: RnEnv2 -> [Var] -> RnEnv2
rnInScope :: Var -> RnEnv2 -> Bool
rnInScopeSet :: RnEnv2 -> InScopeSet
lookupRnInScope :: RnEnv2 -> Var -> Var
type TidyEnv = (TidyOccEnv, VarEnv Var)
emptyTidyEnv :: TidyEnv

Var, Id and TyVar environments (maps)
type VarEnv elt = UniqFM elt
type IdEnv elt = VarEnv elt
type TyVarEnv elt = VarEnv elt
Manipulating these environments
emptyVarEnv :: VarEnv a
unitVarEnv :: Var -> a -> VarEnv a
mkVarEnv :: [(Var, a)] -> VarEnv a
elemVarEnv :: Var -> VarEnv a -> Bool
varEnvElts :: VarEnv a -> [a]
varEnvKeys :: VarEnv a -> [Unique]
extendVarEnv :: VarEnv a -> Var -> a -> VarEnv a
extendVarEnv_C :: (a -> a -> a) -> VarEnv a -> Var -> a -> VarEnv a
extendVarEnvList :: VarEnv a -> [(Var, a)] -> VarEnv a
plusVarEnv :: VarEnv a -> VarEnv a -> VarEnv a
plusVarEnv_C :: (a -> a -> a) -> VarEnv a -> VarEnv a -> VarEnv a
delVarEnvList :: VarEnv a -> [Var] -> VarEnv a
delVarEnv :: VarEnv a -> Var -> VarEnv a
lookupVarEnv :: VarEnv a -> Var -> Maybe a
lookupVarEnv_NF :: VarEnv a -> Var -> a
lookupWithDefaultVarEnv :: VarEnv a -> a -> Var -> a
mapVarEnv :: (a -> b) -> VarEnv a -> VarEnv b
zipVarEnv :: [Var] -> [a] -> VarEnv a
modifyVarEnv :: (a -> a) -> VarEnv a -> Var -> VarEnv a
modifyVarEnv_Directly :: (a -> a) -> UniqFM a -> Unique -> UniqFM a
isEmptyVarEnv :: VarEnv a -> Bool
foldVarEnv :: (a -> b -> b) -> b -> VarEnv a -> b
elemVarEnvByKey :: Unique -> VarEnv a -> Bool
lookupVarEnv_Directly :: VarEnv a -> Unique -> Maybe a
filterVarEnv_Directly :: (Unique -> a -> Bool) -> VarEnv a -> VarEnv a
The InScopeSet type
data InScopeSet

A set of variables that are in scope at some point
Instances

Outputable InScopeSet

Operations on InScopeSets
emptyInScopeSet :: InScopeSet
mkInScopeSet :: VarEnv Var -> InScopeSet
delInScopeSet :: InScopeSet -> Var -> InScopeSet
extendInScopeSet :: InScopeSet -> Var -> InScopeSet
extendInScopeSetList :: InScopeSet -> [Var] -> InScopeSet
extendInScopeSetSet :: InScopeSet -> VarEnv Var -> InScopeSet
modifyInScopeSet :: InScopeSet -> Var -> Var -> InScopeSet
Replace the first `Var` with the second in the set of in-scope variables
getInScopeVars :: InScopeSet -> VarEnv Var
lookupInScope :: InScopeSet -> Var -> Maybe Var
If the given variable was even added to the `InScopeSet`, or if it was the "from" argument of any `modifyInScopeSet` operation, returns that variable with all appropriate modifications applied to it. Otherwise, return `Nothing`
elemInScopeSet :: Var -> InScopeSet -> Bool
uniqAway :: InScopeSet -> Var -> Var
`uniqAway in_scope v` finds a unique that is not used in the in-scope set, and gives that to v.
The RnEnv2 type
data RnEnv2

When we are comparing (or matching) types or terms, we are faced with "going under" corresponding binders. E.g. when comparing:

     \x. e1	~   \y. e2

Basically we want to rename [`x` -> `y`] or [`y` -> `x`], but there are lots of things we must be careful of. In particular, `x` might be free in `e2`, or y in `e1`. So the idea is that we come up with a fresh binder that is free in neither, and rename `x` and `y` respectively. That means we must maintain:

1. A renaming for the left-hand expression

2. A renaming for the right-hand expressions

3. An in-scope set

Furthermore, when matching, we want to be able to have an 'occurs check', to prevent:

     \x. f   ~   \y. y

matching with [`f` -> `y`]. So for each expression we want to know that set of locally-bound variables. That is precisely the domain of the mappings 1. and 2., but we must ensure that we always extend the mappings as we go in.

All of this information is bundled up in the `RnEnv2`

Operations on RnEnv2s
mkRnEnv2 :: InScopeSet -> RnEnv2
rnBndr2 :: RnEnv2 -> Var -> Var -> RnEnv2
`rnBndr2 env bL bR` goes under a binder `bL` in the Left term, and binder `bR` in the Right term. It finds a new binder, `new_b`, and returns an environment mapping `bL -> new_b` and `bR -> new_b`
rnBndrs2 :: RnEnv2 -> [Var] -> [Var] -> RnEnv2
Applies `rnBndr2` to several variables: the two variable lists must be of equal length
rnOccL :: RnEnv2 -> Var -> Var
Look up the renaming of an occurrence in the left or right term
rnOccR :: RnEnv2 -> Var -> Var
inRnEnvL :: RnEnv2 -> Var -> Bool
Tells whether a variable is locally bound
inRnEnvR :: RnEnv2 -> Var -> Bool
rnBndrL :: RnEnv2 -> Var -> (RnEnv2, Var)
Similar to `rnBndr2` but used when there's a binder on the left side only. Useful when eta-expanding
rnBndrR :: RnEnv2 -> Var -> (RnEnv2, Var)
Similar to `rnBndr2` but used when there's a binder on the right side only. Useful when eta-expanding
nukeRnEnvL :: RnEnv2 -> RnEnv2
Wipe the left or right side renaming
nukeRnEnvR :: RnEnv2 -> RnEnv2
extendRnInScopeList :: RnEnv2 -> [Var] -> RnEnv2
rnInScope :: Var -> RnEnv2 -> Bool
rnInScopeSet :: RnEnv2 -> InScopeSet
lookupRnInScope :: RnEnv2 -> Var -> Var
TidyEnv and its operation
type TidyEnv = (TidyOccEnv, VarEnv Var)
When tidying up print names, we keep a mapping of in-scope occ-names (the `TidyOccEnv`) and a Var-to-Var of the current renamings
emptyTidyEnv :: TidyEnv
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