From 0ec171c9aa15390e8579c14d996d1f8be20b7b55 Mon Sep 17 00:00:00 2001
From: Jed Barber <jjbarber@y7mail.com>
Date: Tue, 15 May 2012 00:22:31 +1000
Subject: Added functions to find type variables in terms and types

---
 Term.hs    | 9 ++++++++-
 TypeVar.hs | 5 +++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Term.hs b/Term.hs
index f351714..444ae1a 100644
--- a/Term.hs
+++ b/Term.hs
@@ -147,7 +147,7 @@ rename (TAbs (TVar v) t) vars =
 
 
 typeOf :: Term -> Type
-typeOf (TConst c ty) = ty
+typeOf (TConst _ ty) = ty
 typeOf (TVar v) = varTy v
 typeOf (TAbs v t) = typeFunc (typeOf v) (typeOf t)
 typeOf (TApp f _) = 
@@ -155,6 +155,13 @@ typeOf (TApp f _) =
     last . aType . typeOf $ f
 
 
+typeVarsInTerm :: Term -> Set Type
+typeVarsInTerm (TConst _ ty) = typeVarsInType ty
+typeVarsInTerm (TVar v) = typeVarsInType . varTy $ v
+typeVarsInTerm (TAbs v t) = Set.union (typeVarsInType . varTy $ v) (typeVarsInTerm t)
+typeVarsInTerm (TApp f x) = Set.union (typeVarsInTerm f) (typeVarsInTerm x)
+
+
 mkEquals :: Term -> Term -> Term
 mkEquals lhs rhs =
     let eqConst = TConst (Const (Name [] "=")) (mkEqualsType (typeOf lhs))
diff --git a/TypeVar.hs b/TypeVar.hs
index 049a9e2..904eab7 100644
--- a/TypeVar.hs
+++ b/TypeVar.hs
@@ -63,3 +63,8 @@ mkEqualsType ty = typeFunc (AType [] (TypeOp (Name [] "bool"))) (typeFunc ty ty)
 
 typeFunc :: Type -> Type -> Type
 typeFunc ty1 ty2 = AType [ty1,ty2] (TypeOp (Name [] "->"))
+
+
+typeVarsInType :: Type -> Set Type
+typeVarsInType (TypeVar t) = Set.singleton (TypeVar t)
+typeVarsInType (AType list _) = unions . (map typeVarsInType) $ list
-- 
cgit