diff --git a/fco2/AST.hs b/fco2/AST.hs
index 5af5b99..b214173 100644
--- a/fco2/AST.hs
+++ b/fco2/AST.hs
@@ -94,6 +94,7 @@ data Expression =
   | MostNeg Meta Type
   | SizeType Meta Type
   | SizeExpr Meta Expression
+  | SizeVariable Meta Variable
   | Conversion Meta ConversionMode Type Expression
   | ExprVariable Meta Variable
   | ExprLiteral Meta Literal
diff --git a/fco2/GenerateC.hs b/fco2/GenerateC.hs
index a58c206..d7a10be 100644
--- a/fco2/GenerateC.hs
+++ b/fco2/GenerateC.hs
@@ -326,6 +326,9 @@ genExpression (A.MostNeg m t) = genTypeConstant "mostneg" t
 genExpression (A.SizeExpr m e)
     =  do genExpression e
           tell ["_sizes[0]"]
+genExpression (A.SizeVariable m v)
+    =  do genVariable v
+          tell ["_sizes[0]"]
 genExpression (A.Conversion m cm t e) = genConversion cm t e
 genExpression (A.ExprVariable m v) = genVariable v
 genExpression (A.ExprLiteral m l) = genLiteral l
diff --git a/fco2/Parse.hs b/fco2/Parse.hs
index de48fcc..98698b0 100644
--- a/fco2/Parse.hs
+++ b/fco2/Parse.hs
@@ -662,7 +662,8 @@ sizeExpr
     =  do m <- md
           sSIZE
           (try (do { t <- dataType; return $ A.SizeType m t })
-           <|> do { v <- operand; return $ A.SizeExpr m v })
+           <|> do { v <- operand; return $ A.SizeExpr m v }
+           <|> do { v <- channel <|> timer <|> port; return $ A.SizeVariable m v })
     <?> "sizeExpr"
 
 exprOfType :: A.Type -> OccParser A.Expression
diff --git a/fco2/Types.hs b/fco2/Types.hs
index 4ed1745..af8b6eb 100644
--- a/fco2/Types.hs
+++ b/fco2/Types.hs
@@ -89,6 +89,7 @@ typeOfExpression ps e
         A.MostNeg m t -> Just t
         A.SizeType m t -> Just A.Int
         A.SizeExpr m t -> Just A.Int
+        A.SizeVariable m t -> Just A.Int
         A.Conversion m cm t e -> Just t
         A.ExprVariable m v -> typeOfVariable ps v
         A.ExprLiteral m l -> typeOfLiteral ps l
@@ -122,6 +123,7 @@ isConstExpression ps e
         A.MostNeg m t -> True
         A.SizeType m t -> True
         A.SizeExpr m e -> isConstExpression ps e
+        A.SizeVariable m v -> isConstVariable ps v
         A.Conversion m cm t e -> isConstExpression ps e
         A.ExprVariable m v -> isConstVariable ps v
         A.ExprLiteral m l -> isConstLiteral ps l