[fpc-devel] BOOL

[Michael Van Canneyt]

On Sun, 14 Dec 2014, Florian Klämpfl wrote:

> Am 14.12.2014 um 21:22 schrieb Michael Van Canneyt:
>>
>>
>> On Sun, 14 Dec 2014, Florian Klämpfl wrote:
>>
>>> Am 14.12.2014 um 20:25 schrieb Michael Van Canneyt:
>>>>
>>>>
>>>> On Sun, 14 Dec 2014, Florian Klämpfl wrote:
>>>>
>>>>> Am 14.12.2014 um 18:05 schrieb Adriaan van Os:
>>>>>>> IMHO using the for loop on a non pascal boolean type is simply wrong. At the
>>>>>>> very least the assumption that the false and true are successive, and maybe
>>>>>>> even using BOOL as loopvar in the first place.
>>>>>>
>>>>>> The compiler accepts it.
>>>>>
>>>>> Can somebody with access to delphi please check, if it compiles
>>>>>
>>>>> var
>>>>>  b : bytebool;
>>>>>
>>>>> begin
>>>>>  for b:=false to true do
>>>>>    ;
>>>>> end.
>>>>
>>>> D7 and Delphi XE5 compile it but do not generate code, instead say:
>>>> 'FOR or WHILE loop executes zero times - deleted
>>>> variable b is declared but never used in ...
>>>
>>> But it generates code for
>>>
>>> var
>>>  b : bytebool;
>>> begin
>>> for b:=true to false do
>>>   ;
>>> end.
>>
>> Yes, it does. Strange behaviour :)
>
> Well, true is -1 and false 0 :) I wonder if we should forbid it in fpc mode ...

We should. IMHO ByteBool is unsigned so >=0...

Michael.