Re: Ada standard and maximum line lengths

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

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."

This is followed by the note (maybe only in the AARM, which is what I
have in hand):

"Implementation defined: Maximum supported line length and lexical
element length."

As I understand ARM 2.2(14), it does not define a coupling between
maximum line length and maximum lexical-element length (i.e. maximum
identifier length). It requires both limits to be at least 200
characters, but does not require them to be equal. The limits are stated
in separate sentences -- the two first sentences in the quote.

Perhaps the third and last sentence in ARM 2.2(14), which mentions both
limits in one sentence, confuses the issue. Occasionally, people write
sentences of the form "The A and B are ..." and imply that A and B are
the same.

If the limits are meant to be coupled (equal), there should some text
such as "An implementation shall accept lexical elements that are as
long as the maximum supported line length". But that is not what the ARM
says. And I don't think that one can deduce such a rule just from the
fact that the required minimum limits are both 200 characters.

In the same post in which Jeffrey quoted ARM 2.2(14), it seemed he was
reading it to mean that there is a coupling. I was asking how he deduced
that coupling. I'm asking the same question as you (J-P.), but from the
other side of the burden of proof.

So, can you show the ARM verse that says that a compiler is not allowed
to limit identifiers to 200 characters, if it supports lines of 10,000
characters?

I haven't scanned the whole ARM to see if there is some other text that
requires max line length and max identifier length to be coupled. But it
would be strange to have such text in some other distant part of the
ARM, and not in 2.2 where it would clearly belong.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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