Array in an array

[mnrvovrfc]

I was going to propose using _MEM but...

I was able to note the following:

Code: (Select All)

DIM AS INTEGER abc(1 TO 4)
DIM AS Test xyz(1 TO 10, abc())

That can't be done; at declaration BASIC needs to know what is the extent of the array. That is until something like "variants" and object-like variables is figured out into this implementation.

To try to respond to that, I devised this:

Code: (Select All)

TYPE cardty
    nam AS STRING * 16
    quant AS INTEGER
    e AS _MEM
END TYPE

DIM SHARED card(1 TO 10) AS cardty

RANDOMIZE 1000

card(1).nam = "spade"
card(1).quant = 3
create_card 1
random_card 1
PRINT "The first card for "; card(1).nam; " is "; obtain_card(1, 1)
PRINT "The last card for "; card(1).nam; " is "; obtain_card(1, 3)

set_card 1, 3, 22
PRINT "The last card for "; card(1).nam; " was changed to "; obtain_card(1, 3)

delete_card 1
END

SUB create_card (which AS INTEGER)
    SHARED i0 AS INTEGER
    card(which).e = _MEMNEW(card(which).quant * LEN(i0))
    _MEMFILL card(which).e, card(which).e.OFFSET, card(which).quant, 0 AS INTEGER
END SUB

SUB random_card (which AS INTEGER)
    SHARED i AS INTEGER, i0 AS INTEGER
    FOR i = 1 TO card(which).quant
        _MEMPUT card(which).e, card(which).e.OFFSET + (i - 1) * LEN(i0), INT(RND * 52 + 1) AS INTEGER
    NEXT
END SUB

SUB delete_card (which AS INTEGER)
    _MEMFREE card(which).e
END SUB

SUB set_card (which AS INTEGER, subscr AS INTEGER, valu AS INTEGER)
    SHARED i0 AS INTEGER
    _MEMPUT card(which).e, card(which).e.OFFSET + (subscr - 1) * LEN(i0), valu AS INTEGER
END SUB

FUNCTION obtain_card% (which AS INTEGER, subscr AS INTEGER)
    SHARED i0 AS INTEGER
    obtain_card = _MEMGET(card(which).e, card(which).e.OFFSET + (subscr - 1) * LEN(i0), INTEGER)
END FUNCTION

It's a bit confusing to follow along. Using subprograms makes code easier to read, to make things look as much as possible like multiple-dimension arrays.

Note the UDT variable "cards" is declared with "DIM SHARED" to make life easier into the subprograms. Also note the target type is always "INTEGER" in the _MEM workings, hence the "SHARED i0 AS INTEGER" appearing in a lot of places. The type has to be changed there as well as the last parameter to _MEMFILL, _MEMGET and _MEMPUT. Cannot be an UDT.

With this code, doing:

acard = obtain_card(1, 3)

would be like trying to do:

acard = test(1).abc(3)

in code (according to above) that actually is not possible in QB64(PE).

This code could benefit from some range-checking and other things to make it robust.