[fpc-devel] [Suggestion] Enumeration range-check intrinsic

[Jonas Maebe]

On 13/07/2019 13:52, Michael Van Canneyt wrote:
> 
> 
> On Sat, 13 Jul 2019, Jonas Maebe wrote:
> 
>> On 13/07/2019 13:28, J. Gareth Moreton wrote:
>>> Okay, okay.  So what do we do to stop all these bug reports and help
>>> programmers who get caught out by case blocks raising access
>>> violations?  Are you effectively saying "don't ever use enumerations for
>>> external files and network signals" etc?
>>
>> Declare your enumation types so that the lowest and highest valid value
>> comprise the lowest and highest value representable by its storage:
>>
>> {$mode delphi}
>> {$z1}
>> type
>>  tmyenum = (ea, eb, ec, emax = 255);
>>
>> That behaves the same both in FPC and in Delphi.
> 
> This is a completely pointless definition, since for effective use you
> still need to add code to check that the value is a named one.

That is exactly what this thread is about: the ability to manually check
whether an enumeration value is one of the valid (named) values.


Jonas