Passing 'boxing' values

Monkey Forums/Monkey Programming/Passing 'boxing' values

AdamRedwoods

(Posted 2012) [#1]

I would think that an advantage to boxing would be to create a mutable Integer type when passing values... ?

Class IntBox
	Field value:Int
	
	Method New( value:Int )
	        Self.value=value
	End
	
	Method ToInt:Int()
	        Return value
	End
		
	Method ToString:String()
		Return String(value)
	End
End

Function DoThis(x:Int) ''doesn't work with x:IntBox either
	x=x+1
End

Function Main()
	Local testx:IntBox = New IntBox
	testx = 1

	DoThis(testx) '' x=x+1
	Print (testx) '' why isn't this 2?
End

Jimbo

(Posted 2012) [#2]

I'm new to Monkey but it looks as though DoThis() should have a return statement. I assume Monkey parameters are passed by value and not be reference.

AdamRedwoods

(Posted 2012) [#3]

You are correct, but I was trying to leverage 'boxing' where you can place an object in place of an Int type.

I'm starting to think monkey will convert IntBox to an Int, using the ToInt() method, thus ignoring the object.
I was THINKING that monkey trans did it the OTHER way, where it would sub x in DoThis() with IntBox.value-- but I understand what's going on now.

If I added a method to IntBox called AddOne()

Method AddOne()
     value += 1
End

Then I could pass IntBox around like an Int, but use the method AddOne() as well.