replace ding in map'

diff --git a/sem.icl b/sem.icl
index ab7aa9c..1bedd62 100644 (file)
--- a/sem.icl
+++ b/sem.icl
@@ -129,7 +129,20 @@ instance unify Expr where
     where m = typeExpr e >>= \tex-> unify t tex 
 
 replace :: String Type -> Env Void
-replace _ _ = undef
+replace ident type = get >>= \(st, fr)->put ('Map'.fromList $ 
+               map (itupdate ident type) ('Map'.toList st), fr)
+       where
+               itupdate :: String Type (String, Type) -> (String, Type)
+               itupdate ident newtype ov=:(key, IdType type) = if (ident == type)
+                       (key, newtype) ov
+               itupdate ident newtype (key, TupleType (t1, t2))
+               # (_, t1) = itupdate ident newtype (key, t1)
+               # (_, t2) = itupdate ident newtype (key, t2)
+               = (key, TupleType (t1, t2))
+               itupdate ident newtype (key, ListType t1)
+               # (_, t1) = itupdate ident newtype (key, t1)
+               = (key, ListType t1)
+               itupdate _ _ k = k
 
 instance unify Type where
        unify IntType IntType = pure IntType