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+--- Thread: DIM AT -- feature request (/showthread.php?tid=1902)
DIM AT -- feature request - Jack - 08-14-2023
PowerBasic has a very handy feature, the ability to dim at a certain address, for example suppose that you want to use a fixed-length string as a memory buffer
DIM buff As String * 256
DIM m(31) AS _Unsigned Long AT VARPTR(buff)
then you could access the array as usual but the values of the array m would be stored in the string buff
since QB64pe lacks arrays in Type, you could almost have that flexibility if you had Dim At
RE: DIM AT -- feature request - mnrvovrfc - 08-14-2023
The "DIM" statement presented there looks confusing.
Therefore after many years I'm glad QB64 instead has _MEM and _OFFSET.
I understand, use "m(1), m(2)" etc. to access portions in "buff", but yet this could be simplified with _MEMGET and _MEMPUT wrapped into convenience functions. Because we are all using 64-bit there would be no performance penalty for it.
RE: DIM AT -- feature request - grymmjack - 08-15-2023
Hi @Jack
I just stumbled onto this in the issue tracker:
https://github.com/QB64-Phoenix-Edition/QB64pe/issues/354#issuecomment-1611346466
mechatronic3000 Wrote:I ran into a similar issue with my 2d physics engine. What I ended up doing is making the arrays into _MEM's (essentially making it a pointer) and I created some getters and setters to extract my data from the _MEM array.
Here is an example of what I did. You can make "test" and array in itself, however you have to do a _memnew for each element in the array.
Code: (Select All)
TYPE Example
Parameter1 AS INTEGER
Parameter2 AS INTEGER
Parameter3 AS _MEM
END TYPE
DIM test AS Example: test.Parameter3 = _MEMNEW(2 * 10) ' sizeof Integer * Number of elements
setter test, 2, 5
setter test, 6, 3
setter test, 9, 1
PRINT getter(test, 2)
PRINT getter(test, 6)
PRINT getter(test, 9)
SUB setter (test AS Example, index AS LONG, value AS INTEGER)
_MEMPUT test.Parameter3, test.Parameter3.OFFSET + (index * 2), value AS INTEGER
END SUB
FUNCTION getter% (test AS Example, index AS LONG)
getter = _MEMGET(test.Parameter3, test.Parameter3.OFFSET + (index * 2), INTEGER)
END FUNCTION
This might help you as it helped me.