fixed functions without input

resources/Rosetta/test-multiple.rosetta

@@ -63,3 +63,45 @@ type Contract_Get:
   contract Contract (1..1)
 type Contract_Anytime:
   contract Contract (1..1)
+
+func MkZero:
+  output:
+    contract Contract (1..1)
+  assign-output contract -> zero -> unit:
+    1 // create the zero contract dummy value
+
+func MkExpired:
+  output:
+    contract Contract (1..1)
+  assign-output contract -> expired -> unit:
+    1 // create the expired contract dummy value
+
+func MkOne:
+  inputs:
+    currency UnitType (1..1)
+  output:
+    contract Contract (1..1)
+  assign-output contract -> one -> currency:
+    currency
+
+func MkOr:
+  inputs:
+    left  Contract (1..1)
+    right Contract (1..1)
+  output:
+    contract Contract (1..1)
+  assign-output contract -> orContract -> left:
+    left
+  assign-output contract -> orContract -> right:
+    right
+
+func MkBoth:
+  inputs:
+    left  Contract (1..1)
+    right Contract (1..1)
+  output:
+    contract Contract (1..1)
+  assign-output contract -> both -> left:
+    left
+  assign-output contract -> both -> right:
+    right

src/Parser/Function.hs

@@ -37,8 +37,10 @@ assignmentParser =
 inputAttributesParser :: Parser [TypeAttribute]
 inputAttributesParser =
     do
-        _ <- lexeme $ string "inputs:"
-        many $ try attributeParser
+        inp <- observing $ lexeme $ string "inputs:"
+        case inp of
+            Left _ -> return []
+            Right _ -> many $ try attributeParser
 
 -- |Parses the output attribute of a function statement in Rosetta into a TypeAttribute
 outputAttributeParser :: Parser TypeAttribute