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Merge pull request #94 from thomwiggers/master

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Use name instead of Var as type for variable names
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Stephen Diehl 2017-04-19 19:42:33 +01:00 committed by GitHub
commit ae73485e04
1 changed files with 5 additions and 5 deletions
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006_hindley_milner.md
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@ -208,11 +208,11 @@ Context
The typing context or environment is the central container around which all
information during the inference process is stored and queried. In Haskell our
implementation will simply be a newtype wrapper around a Map of ``Var`` to
implementation will simply be a newtype wrapper around a Map of ``Name`` to
``Scheme`` types.
```haskell
newtype TypeEnv = TypeEnv (Map.Map Var Scheme)
newtype TypeEnv = TypeEnv (Map.Map Name Scheme)
```
The two primary operations are *extension* and *restriction* which introduce or
@ -230,7 +230,7 @@ Operations over the context are simply the usual Set operations on the
underlying map.
```haskell
extend :: TypeEnv -> (Var, Scheme) -> TypeEnv
extend :: TypeEnv -> (Name, Scheme) -> TypeEnv
extend (TypeEnv env) (x, s) = TypeEnv $ Map.insert x s env
```
@ -648,11 +648,11 @@ context.
Var x -> lookupEnv env x
```
The function ``lookupVar`` looks up the local variable reference in typing
The function ``lookupEnv`` looks up the local variable reference in typing
environment and if found it instantiates a fresh copy.
```haskell
lookupEnv :: TypeEnv -> Var -> Infer (Subst, Type)
lookupEnv :: TypeEnv -> Name -> Infer (Subst, Type)
lookupEnv (TypeEnv env) x = do
case Map.lookup x env of
Nothing -> throwError $ UnboundVariable (show x)