Plse make 'external' consts usable in other 'external' defs

[Dany]

Please make 'external' constants usable in other 'external' constants definitions.

e.g. I would like to be possible:

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const ArraySize: byte; external;
const MyArray[ArraySize]: array of byte; external;// first external constant is already used here

Currently the second line gives a compiler error.

I have to use instead:

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const ArraySize: byte; external;
const MyArray[10]: array of byte; external; // here 10 is an arbitrary byte value

Above compiles well, but "SizeOf(MyArray)" always returns 10, irrespective of the actual size, so this function can not be used now on external constants.

Thanks in advance!

[janko.kaljevic]

Hello,

This implementation would require dynamic arrays and they must be in RAM. So there is no way to declare constant array like this.

Best regards.

[Dany]

Hello,

This implementation would require dynamic arrays and they must be in RAM. So there is no way to declare constant array like this.

Best regards.

Ok, thanks! Keep up the good work!

[janni]

This implementation would require dynamic arrays and they must be in RAM. So there is no way to declare constant array like this.

This doesn't seem to be the problem here - all constants are available at compile time. Looking at present compiler possibilities, what Dany asks for is more change of notation, than something really new.
Please notice, that it doesn't matter what size of constant array is declared as external. The size is determined by the declaration in a parent unit/main and it cannot be any other way (if both sizes were to be taken into account, discrepancies would have to lead to an error, so it would be one size anyway).

One may already declare

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const ArraySize: byte; external;
const MyArray: array[1] of byte; external; // size given here is not decisive

and, in the parent unit

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const ArraySize=5;
const MyArray: array[ArraySize] of byte=(0,1,2,3,4);

which in effect produces constant array of 5 elements. And one may now use ArraySize as size of MyArray in the child unit, though it would be better if SizeOf could produce valid result, as well.

The notation proposed by Dany

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const ArraySize: byte; external;
const MyArray: array[ArraySize] of byte; external;

is actually showing a way for easy implementation of proper operation of SizeOf in such cases. (Naturally, in some future, SizeOf should produce valid results, whatever the notation, and there should be no need to provide sizes with no real meaning in external declarations.)