Possible bug with array of objects

[LeslieS]

It seems an instance of an object stored in an array cannot be referenced.
Given the class:

' CTest2
option Compatible 
option ClassModule 
option Explicit 
	
	public n as integer
	
	private sub class_initialize() 
	end sub 

The following message box shows that r does not reference a(1). It prints ‘0’

sub testit() 
	dim a(1 to 2) as CTest2 
	dim r as CTest2 
	set a(1) = new CTest2 
	a(1).n = 12
	r = a(1) 
	msgbox(r.n)
	dim b as CTest2
	set b = new CTest2
	b.n = 12
	r = b
	msgbox(r.n)
end sub 

When r is assigned to b, the reference works as expected and shows ‘12’.

[joshua4]

I see where the question is coming from, definitely. But actually a(1).n can be referenced. Replace the first msgbox(r.n) with msgbox(a(1).n) and the code works as expected.

For another example, return to msgbox(r.n) but change the preceding line from r = a(1) to r.n = a(1).n. This also works as expected.

The problem rather seems to be assigning from a(1) to r. Since we don’t have VarPtr (a la VBA), it’s tricky to see more of what is going on, but I definitely can replicate the behavior with Calc 6.4.2.2.

You would imagine that the object reference stored in a(1) would just be passed to r with the assignment r = a(1). I checked to see if Newing r had any effect, but you can Dim r as Object or even Variant with the same results.

Dimming r as Object does show, however, that something is happening with r = a(1). If you Dim r as Object you can still run the code and get the 0-valued message box. Now, if you Rem out the r = a(1) you, of course, get an error since BASIC knows of no n member for the generic object r. So it is like you are in copy semantics and setting r to the class but getting a new variable table, i.e., no cloning.

Have you tried properties in the CTest2 class?

[joshua4]

Here are two straightforward workarounds that are still very basic LO BASIC syntax:

@LeslieS

sub testit() 
	dim a(1 to 2) as new CTest2 'New in original Dim
	dim r as CTest2 
	'set a(1) = new CTest2 'Do not New after original Dim
	a(1).n = 12
	r = a(1) 
	msgbox(r.n)
	dim b as CTest2
	set b = new CTest2
	b.n = 12
	r = b
	msgbox(r.n)
end sub 

Or accept a() as Variant:

@LeslieS

sub testit() 
	dim a(1 to 2) as Variant 'As Variant
	dim r as CTest2 
	dim i as integer
	for i = LBound(a) to UBound(a)
		a(i) = new CTest2
	next i
	a(1).n = 12
	r = a(1) 
	msgbox(r.n)
	dim b as CTest2
	set b = new CTest2
	b.n = 12
	r = b
	msgbox(r.n)
end sub