[fpc-devel] Minor debate with ISO standard on case blocks

[J. Gareth Moreton]

Yeah, I don't find that description clear either.  One shouldn't have to 
be a lawyer in order to decrypt such standards!

Of course, FPC can follow its own standard, but it should be one that 
everyone agrees on.  While I think we shouldn't live in the shadow of 
Delphi or be jammed in the realm of backwards compatibility, I'm a bit 
wary if there are quirks or errors that might otherwise cause people to 
back away from FPC rather than adapt their code to conform to it.

But just from a practicality point of view, I think a run-time error is 
better in this instance because you may be able to justify a particular 
input value not being possible, and so not need to add code for it in 
your case block, but if such a value ends up reaching the case block 
anyway, then you deserve to endure a run-time error because it means you 
haven't covered it properly.

Speaking of books and documentation, what's out there for Free Pascal in 
particular?

Gareth aka. Kit

P.S. I like to think my own design specs are a lot clearer than that ISO!


On 30/07/2019 09:29, Michael Van Canneyt wrote:
>
>
> On Tue, 30 Jul 2019, thaddy wrote:
>
>> Telling.
>>>
>>> NOTES
>>>
>>> 1. If it is possible to construct a program in which the violation or
>>> non-violation of this International Standard requires knowledge of the
>>> data read by the program or the implementation definition of
>>> implementation-defined features, then violation of that requirement is
>>> classified as an error. Processors may report on such violations of
>>> the requirement without such knowledge, but there always remain some
>>> cases that require execution, simulated execution, or proof procedures
>>> with the required knowledge. Requirements that can be verified without
>>> such knowledge are not classified as errors.
>
> Hm.
>
> Even after reading this 5 times, I still am not sure I understand the
> above. The people who wrote this must have been either extraordinary 
> geniuses, or very confused minds.
>
> Or else they wanted to give a befriended unemployed lawyer some work.
> But anyone writing such a paragraph deserves to be unemployed... ;)
>
> How you're suppsed to construct a working & compliant 'processor' (I 
> assume this means compiler or interpreter or somesuch) after reading 
> this is a mystery to me.
>
> Michael.
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>
>

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