[fpc-pascal] Set size limit

[Jonas Maebe]

On 11 Mar 2013, at 14:32, Daniel Gaspary wrote:

> In my case the enum has near 600 elements.
>
> TMyEnum = (me1, me2...);
>
> The set though would never be used to contain more than 256.
>
> TMySet = set of TMyEnum;
>
> Is it not viable to modify the compiler to compile the code and raise
> an exception if I try to add more than 256 elements to the set ?

A set is basically a bitpacked array of boolean. Element X is set to  
true if you add X to the set, and to false if you remove it again.  
That means that if you have a set with 600 possible values, you need  
at least 600 bits, regardless of how many elements are inside it.

The above also shows an alternative to sets in that case: you can use  
a bitpacked array[TMyEnum] of boolean instead. Of course, then you  
can't use the regular set operators.


Jonas
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