X-Git-Url: https://git.martlubbers.net/?a=blobdiff_plain;f=AST.dcl;h=f415045667666543e436a1d621a471cbe7718ede;hb=5573b4ce8215a277a82146a8dae4c4e7ef205bd8;hp=e9c694486eb02e9eddcfaf2c0c08445c95b1996b;hpb=43f59bf00c11cfbeee906b16063abfca6f4c09cc;p=cc1516.git

diff --git a/AST.dcl b/AST.dcl
index e9c6944..f415045 100644
--- a/AST.dcl
+++ b/AST.dcl
@@ -1,7 +1,7 @@
 definition module AST
 
 from Data.Maybe import :: Maybe
-from StdOverloaded import class toString, class ==, class <
+from StdOverloaded import class toString, class ==, class zero, class <
 
 :: Pos = {line :: Int, col :: Int}
 :: AST = AST [FunDecl]
@@ -41,6 +41,8 @@ from StdOverloaded import class toString, class ==, class <
 instance toString Pos
 instance toString Type
 instance toString AST
+
+instance zero Pos
 instance == Op1
 instance == Op2
 instance < Op1