Re: Ada standard and maximum line lengths

["Randy Brukardt" <randy@rrsoftware.com>]

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"Niklas Holsti" <niklas.holsti@tidorum.invalid> wrote in message 
news:amo8u2Fh3ngU1@mid.individual.net...
> On 13-01-28 22:46 , J-P. Rosen wrote:
>> Le 28/01/2013 21:22, Niklas Holsti a �crit :
>>> My point is that the compiler's max identifier length can be *less* than
>>> its max line length.
>> Can you point the RM verse that allows you to think that the compiler is
>> allowed to put a max to an identifier length, other than the one that
>> results "naturally" from the max line length?
>
> ARM 2.2(14), the same part that Jeffrey quoted:
>
> "An implementation shall support lines of at least 200 characters in
> length, not counting any characters used to signify the end of a line.
> An implementation shall support lexical elements of at least 200
> characters in length. The maximum supported line length and lexical
> element length are implementation defined."

Interestingly, the ACATS (and ACVC before it) has always assumed that the 
only limit is the one on the line length. The ACATS has tests parameterized 
by line length, and these include identifiers up to the line length -- an 
implementation would have to get a waiver to make the identifier length 
shorter than the line length. So far as I know, no one has ever asked.

Ada 83 had no explicit allowance for limitations, which is probably where 
the ACATS gets its requirements from. Ada 95 tried to add a minimum line 
length, but seems to have (unintentionally?) allowed identifiers shorter 
than the full line length. I tend to agree with your reading of the RM, but 
it doesn't match practice because of course implementations also have to 
follow the ACATS requirements.

                                   Randy.