20 lines
577 B
Haskell
20 lines
577 B
Haskell
|
module Enviroment where
|
||
|
|
|
||
|
|
import qualified Data.Map as M
|
||
|
|
import ExprType
|
||
|
|
import Data.Maybe
|
||
|
|
|
||
|
|
data Enviroment = Enviroment (M.Map String Expr) (Maybe Enviroment)
|
||
|
|
|
||
|
|
base :: Enviroment
|
||
|
|
base = Enviroment (M.fromList [
|
||
|
|
("test-var", IntE 10)
|
||
|
|
]) Nothing
|
||
|
|
|
||
|
|
lookupVar :: Enviroment -> String -> Maybe Expr
|
||
|
|
lookupVar (Enviroment menv upperEnv) var = let mExpr = M.lookup var menv in
|
||
|
|
if isNothing mExpr then upperEnv >>= (`lookupVar` var) else mExpr
|
||
|
|
|
||
|
|
insertVar :: Enviroment -> String -> Expr -> Enviroment
|
||
|
|
insertVar (Enviroment menv u) var expr = Enviroment (M.insert var expr menv) u
|