Re: Gnat 2013 is out!

[Bill Findlay <yaldnif.w@blueyonder.co.uk>]

Dennis Lee Bieber <wlfraed@ix.netcom.com> wrote:
> On Thu, 30 May 2013 09:01:17 +0100, Bill Findlay
> <yaldnif.w@blueyonder.co.uk> declaimed the following in comp.lang.ada:
> 
>> 
>> The worst 'program' I ever saw was 'written' in 'FORTRAN'.
>> Yes, those quotes are meant to scare you.
>> 
>> In the mid 80s a graduate student visiting Glasgow was sent to me for help.
>> A program, which she had brought with her from an even more ancient seat of
>> learning, would not work on the GU Computing Service computer.
> 
> 	<snip>
> 
>> Each subroutine had many parameters, the actual parameters of most calls
>> being being a selection of variables from the COMMON areas.
>> 
>> Variables in COMMON were also used directly.
>> Many times. Many, many times. Many times.
>> 
> 
> 	Ouch! While FORTRAN's pass-by-reference could be dangerous (the
> infamous [and maybe urban legend] non-constant constant in some early
> compilers) when the same actual is provided to multiple arguments,
> mixing COMMON and argument passing at the same time is something I never
> encountered.

The non-constant constant actually happened to me in my first real FORTRAN
program.

I called a routine that took a desired error parameter, which I wrote as
0.0;
not noticing that the same parameter was used to return an achieved error
estimate.

The following arithmetic IF malfunctioned bafflingly until I realised that
0.0 was being redefined!

-- 
Bill Findlay