function output error messages looking good, need more tests

src/ytdl_sub/script/types/array.py

@@ -18,6 +18,10 @@ from ytdl_sub.script.types.variable_dependency import VariableDependency
 class Array(NonHashable):
     value: List[Resolvable]
 
+    @classmethod
+    def human_readable_name(cls) -> str:
+        return "Array"
+
 
 @dataclass(frozen=True)
 class UnresolvedArray(Array, VariableDependency, FutureResolvable):

src/ytdl_sub/script/types/function.py

@@ -207,7 +207,13 @@ class BuiltInFunction(Function):
         received_type_names: List[str] = []
         for arg in self.args:
             if isinstance(arg, BuiltInFunction):
-                received_type_names.append(f"%{arg.name}(...)->{arg.output_type.__name__}")
+                if is_union(arg.output_type):
+                    # TODO: Move naming to separate function, deal with Union input naming
+                    received_type_names.append(
+                        f"%{arg.name}(...)->Union[{', '.join(arg_type.human_readable_name() for arg_type in arg.output_type.__args__)}]"
+                    )
+                else:
+                    received_type_names.append(f"%{arg.name}(...)->{arg.output_type.__name__}")
             else:
                 received_type_names.append(arg.__class__.__name__)
 

src/ytdl_sub/script/types/map.py

@@ -20,6 +20,10 @@ from ytdl_sub.utils.exceptions import StringFormattingException
 class Map(NonHashable):
     value: Dict[Hashable, Resolvable]
 
+    @classmethod
+    def human_readable_name(cls) -> str:
+        return "Map"
+
 
 @dataclass(frozen=True)
 class UnresolvedMap(Map, VariableDependency, FutureResolvable):

src/ytdl_sub/script/types/resolvable.py

@@ -15,7 +15,9 @@ class ArgumentType(ABC):
     Any possible argument type that has not been resolved yet
     """
 
-    pass
+    @classmethod
+    def human_readable_name(cls) -> str:
+        return cls.__name__
 
 
 class AnyType_0(ABC):