Huh?

3or4/Interpreter/Self.hs

@@ -47,41 +47,18 @@ substBrExp =
 
 substExp :: Exp
 substExp =
-  parse
-  "( \\map. \\substBr. \\elem. \\equal. \\if. \\var. \\e. rec subst = \\x. case x of\
-  \ { Apply(e1,e2) -> Apply(subst e1, subst e2) \
-  \ ; Lambda(x,y) -> if (equal x var) Lambda(x,y) Lambda(x,subst y) \
-  \ ; Var(x) -> if (equal x var) e Var(x) \
-  \ ; Const(c,es) -> Const(c, map subst es) \
-  \ ; Rec(x, e') -> if (equal x var) Rec(x,e') Rec(x,subst e')\
-  \ ; Case(e',bs) -> Case(subst e', map (substBr subst var) bs) \
-  \ }) \
-  \  \
-  \ -- map \
-  \ (\\f. rec map = \\xs. case xs of \
-  \ { Nil() -> Nil() \
-  \ ; Cons(x,xs) -> Cons(f x, map xs)\
-  \ }) \
-  \ -- substBr \
-  \ (\\subst. \\var. \\b. case b of \
-  \ { Branch(c,vs,e') -> if (elem var vs) Branch(c,vs,e') Branch(c,vs, subst e') \
-  \ }) \
-  \ -- elem \
-  \ (\\x. rec elem = \\l. case l of \
-  \ { Nil() -> False() \
-  \ ; Cons(v,vs) -> if (equal x v) True() (elem vs)\ 
-  \ }) \
-  \ -- equal \
-  \ (rec equal = \\m. \\n. case m of \
-  \ { Zero() -> case n of { Zero() -> True(); Suc(n) -> False() } \
-  \ ; Suc(m) -> case n of { Zero() -> False(); Suc(n) -> equal m n }\
-  \ }) \
-  \ -- if \
-  \ (\\b. \\t. \\f. case b of \
-  \ { True() -> t \
-  \ ; False() -> f \
-  \ }) \
-  \"
+  subst (Variable "if") ifExp .
+  subst (Variable "equal") equalExp .
+  subst (Variable "substBr") substBrExp .
+  subst (Variable "map") mapExp $ parse
+        "\\var. \\e. rec subst = \\x. case x of\
+        \ { Apply(e1,e2) -> Apply(subst e1, subst e2) \
+        \ ; Lambda(x,y) -> if (equal x var) Lambda(x,y) Lambda(x,subst y) \
+        \ ; Var(x) -> if (equal x var) e Var(x) \
+        \ ; Const(c,es) -> Const(c, map subst es) \
+        \ ; Rec(x, e') -> if (equal x var) Rec(x,e') Rec(x,subst e')\
+        \ ; Case(e',bs) -> Case(subst e', map (substBr subst var) bs) \
+        \ }"
 
 -- Task 4