Working out concatenation of two arrays

I’m a newbie in XOJO and I’m trying to work out what happens in the code below specifically the concatenation of what seems to be 2 arrays.

This comparison has been used severally in the code I’m looking at and is part of a much larger program used for the generation of .tcx FILES.

if yeararray(drawlogdate.year)<>nil and yeararray(drawlogdate.year).dayarray(drawlogdate.dayofyear)<>nil then

Note:
yeararray is an array yeararray(2100)
drawlogdate is an arrray of type date

My interpretation of 1ST segment of the IF statement above:

1 - Fetch year segment of date and store this in the array yeararray
2 - Check if yeararray(drawlogdate.year) is not equal to zero

My interpretation of 2ND segment of the IF statement above:

1 - Fetch year segment of date and store this in the array yeararray
2 - Fetch dayofyear segment of date and store this in the array dayarray
3 - Concatenate yeararray and dayarray and check the outcome is not NIL … Here I dont get how the concatenation is done?

Thanks for any help

Apologies … ignore what I said below in my original post:

yeararray is an array yeararray(2100)
drawlogdate is an arrray of type date

Having looked at the code better:
yeararray is a class.
drawlogdate is a class.

But I’m still wondering how class concatenation work out in XOJO.

There is no concatenation in the above code. And is a logical comparison operator in the above code.

And drawlogdate is probably a Date (not an array of Date).

@Eli Ott … thanks … What exactly does the dot operator when linkin g the yeararray and the dayarray not with regards to the referencing of the classes yeararray and dayarray

What you have is dereferencing a pointer. The best explanation I can come up with is to think of it as if the compiler were creating several temporary variables for you. You can deconstruct the line of code like this:

if yeararray(drawlogdate.year).dayarray(drawlogdate.dayofyear) <> nil then

is equivalent to

dim tempYear as integer
dim tempDayOfYear as integer
dim tempArrayYear as YearArrayClass   // whatever that is defined as
dim tempArrayDayArray() as DayArrayClass    // whatever that is defined as
dim tempArrayDay as DayArrayClass

tempYear = drawlogdate.year
tempDayOfYear = drawlogdate.dayofyear

tempArrayYear = yeararray(tempYear)
tempArrayDayArray = tempArrayYear.dayarray
tempArrayDay = tempArrayDayArray(tempDayOfYear)

if tempArrayDay <> nil then