Re: Ada standard and maximum line lengths

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

"Robert A Duff" <bobduff@shell01.TheWorld.com> wrote in message 
news:wccfw1iheq9.fsf@shell01.TheWorld.com...
...
> I'd prefer not to have such built-in limits.  The fact that I've
> never seen an identifier longer than 73 characters doesn't change
> my mind.  To argue for a built-in limit of 200 characters, I think
> you have to not only argue that "nobody needs lines longer than that",
> but also argue that there is some important advantage (efficiency?
> simplicity?), which I don't see here.

There is an effciency advantage, but whether it is important today I can't 
say. Specifically, the position value for a line can be limited to 8-bits if 
you limit lines to 250 characters. Having such a limit reduces the size of 
writes done by our compiler's first pass by roughly 15%, and given that the 
compiler was completely disk-bound, that effectively reduced the runtime of 
that pass by a corresponding amount (it also saved a similar amount of time 
in later passes reading the data back in). Whether that's still true on 
current machines I don't know (it seems likely that there is still some cost 
for reading/writing 15% more data that would 98% of the time carry no 
information). (I probably wouldn't architect a new compiler like Janus/Ada 
is, as memory savings is not an important criteria today, but I still 
wouldn't like wasting significant amounts of memory (line/position 
information being stored in almost every symbol table entry) to carry almost 
no information.

                                                Randy.