New Alpha_(re)

Thu, 3 Apr 1997 09:51:31 -0800 (PST)

>  (*** Does anybody know how UCSD behaves here?  I don't want to dig
>  out my old Apple //e in order to check this. ***)

Yes, it clips strings and it has a 10 for the default field size.
Borland is the only Pascal compiler that I have used or heard of that does 
not clip strings and uses 1 as the default field size.  Does someone
know of another one (besides gpc)?

>The above does not clarify how GPC's default behaviour should be.
It should be ISO Pascal with the de-facto-standard field widths.

>IMHO Borland's method is more logical than what most Standard Pascal
>compilers do. 
It may be more logical, but we didn't design the language.  

>However the only true contradiction between Borland and
>ISO in this context is string clipping which only occurs in very rare
>cases (at least in my programs).
It happens in quite a few places in my programs.  In fact, it breaks one
of my standard teaching examples to show students the power of Pascal. 
(Write a program to print a right triangle of stars (*).)

>Thus I could live with string clipping
>being "on" by default.  Concerning field widths, it does not contradict
>ISO Standard to follow Borland, so we should do that.  (Remember that
>`--borland-pascal' turns string clipping off and that `--standard-pascal'
>makes GPC behave like other Standard Pascal compilers.)

I can not live with either being the standard behavior.  If you do make
Borland behavior standard, at least make it a configure option to not
make Borland behavior standard so I don't have to maintain local changes
to gpc to get what I really want.  Similarly, if you choose to make
Standard Pascal the default behavior, have a configure option to choose
Borland for those who want it.  Better yet, make gpc change depending
on whether it is run as gpc (Standard Pascal) or bpc (Borland Pascal).

>  * When an Integer value is being output with a field width of zero,
>    output is suppressed.  Is this ISO Standard (doesn't seem so),
>    or a bug?

This is not conforming and needs to be changed.  It should be the same as 1.

>  * When a Real value is being output with a too narrow field width,
>    other compilers bother to make the output as short as possible.
>    Should GPC do the same?

It should follow 6.9.3.4.1 (ISO 7185) which says:

    if TotalWidth >= ExpDigits + 6
	then ActWidth := TotalWidth
	else ActWidth := ExpDigits + 6;

where ActWidth is the actual number of characters written, yeilding the 
format SV.V+EE  where is S is - or blank, V.V is the number, EE is
the exponent. (+ could be -).

>  * All Pascal compilers I have access to have the "feature" that it is
>    impossible to output a positive Real value without at least one
>    leading blank.  This is annoying in some situations, so what about
>    an additional switch, e.g. `--no-real-blank', to disable it
>    optionally?  (Better suggestions for the names of all compiler
>    switches are welcome!)

Yes, they are following the standard.  I have no problem with the switch
as long as it is not standardly on.

Is it possible we should ask Juki what the standard behavior should be?
Borland vs Standard?

-- 
Phil Nelson                       NetBSD: http://www.netbsd.org
e-mail: phil@cs.wwu.edu           LPF: http://www.lpf.org
http://www.cs.wwu.edu/~phil       !gifs: http://www.lpf.org/Patent/Gif/Gif.html

Phil Nelson (phil@cs.wwu.edu)