Object to function pointer?

BlitzMax Forums/BlitzMax Programming/Object to function pointer?

Regular K

(Posted 2006) [#1]

Im using TMap to store a string as a key, with a function pointer as the value. I have to force both as objects when inserting them into the map. How do I get the function pointer back and call it?!

Im a bit stumped here...

Function CreateEntityByClassname:TEntity(Class:String)
	If MapContains(TEntity.Classes,Class)
		Local c()=MapValueForKey(TEntity.Classes,Class)
		Return c()
	EndIf
	Return Null
End Function

Function RegisterClass(cr:TEntity(),name:String)
	MapInsert(TEntity.Classes,Object(name),Object(cr()))
End Function

Theres some code for you.

What im tryign to exactly do is register a creation function with a classname for each entity. When you want to create that entity, you call CreateEntityByClassname with the class you want to create, it will then call that entities classnames creation function and return the entity created.

The creation function isn't in a type or a method.

marksibly

(Posted 2006) [#2]

Hi,

You can't convert between object<->function.

You'll have to create a wrapper object for the function, eg (untested):

Type TEntityCreator
   Method CreateEntity:TEntity()
     Return _cr()
   End Method

   Function Create:TEntityCreator( cr:TEntity() )
     Local t:TEntityCreator=New TEntityCreator
     t._cr=cr
     Return t
   End Function
   Field _cr:TEntity()
End Type

Function CreateEntityByClassname:TEntity(Class:String)
  Local c:TEntityCreator=TEntityCreator( MapValueForKey( TEntity.Classes,Class ) )
  If c Return c.CreateEntity()
  Throw "Unrecognized Classname:"+Class
End Function

Function RegisterClass(cr:TEntity(),name:String)
  MapInsert TEntity.Classes,name,TEntityCreator.Create( cr )
End Function

Regular K

(Posted 2006) [#3]

Thank you, that seems to be working :)