Implementing support for function objects that only take one tuple pa…

…ramter

src/main/java/de/uni/bremen/monty/moco/visitor/ResolveVisitor.java

@@ -431,6 +431,17 @@ public void visit(FunctionCall node) {
 			}
 			Declaration callableDeclaration = overloadResolution(argTypes, scope.resolveFunction(node.getIdentifier()));
 
+			// if the parameter is just one tuple, we might have to unpack it
+			if ((callableDeclaration == null) && (argTypes.size() == 1)
+			        && (argTypes.get(0).getIdentifier().getSymbol().startsWith("Tuple"))) {
+				List<ClassDeclaration> argCls = ((ClassDeclarationVariation) argTypes.get(0)).getConcreteGenericTypes();
+				argTypes = new ArrayList<>(argCls.size());
+				for (ClassDeclaration cls : argCls) {
+					argTypes.add(cls);
+				}
+				callableDeclaration = overloadResolution(argTypes, scope.resolveFunction(node.getIdentifier()));
+			}
+
 			if (callableDeclaration instanceof FunctionDeclaration) {
 				FunctionDeclaration function = (FunctionDeclaration) callableDeclaration;
 				node.setDeclaration(function);

src/test/resources/testPrograms/functionObjects/tuple1function.monty

@@ -0,0 +1,14 @@
+// Testing: 1-Tuple function objects without 1-Tuples
+//
+// Expected Output: 1\n8\n
+
+// a function that takes exactly one tuple
+Int takeFirst( (Int, Int) t):
+    return t._1
+// and a function variable that points to this function
+(Int, Int) -> Int fn := takeFirst
+
+// call the function the standard way
+println(takeFirst((1,2)))
+// call the function variable with a tuple
+println( fn((8,2)) )

src/test/resources/testPrograms/functionObjects/tuple1function.output

@@ -0,0 +1,2 @@
+1
+8