Re: Ada Quality and Style book discussion

[Anonymous Coward <spam@spam.com>]

In article <dlelkn$g6l$1@nwrdmz03.dmz.ncs.ea.ibs-infra.bt.com>, 
Martin Dowie wrote:
> 
> I'm with Simon on this one. "Today" or "This_Day" or "The_First_Day"
> are better variable names...

"Today" and "The_First_Day" are better variable names if the objects
really have those meanings; but "This_Day" is lousy, because any noun
(and non-boolean objects should be nouns) can follow "This_", which is
completely meaningless.  "_Type" is meaningful, because it indicates a
user defined type.  

"A_" and "An_" is almost as meaningless as "This_", because *most*
objects in a system are singular.  It's far less noise to make plural
objects to stand out by adding an "s" or "_Array" or "_List".

> ...however, there are times when there are name clashes and (for no
> good reason that I can think of) Ada can't tell the difference
> between a types name and, say, an enumerate.
> 
> So, instead of appending the ugly "_Type", I prefer to use the
> English as my inspiration and prefix "A_" or "An_". Types are after
> all "indefinite articles". Objects are "definite articles".
> 
> E.g.
> 
>     My_New_Saab : A_Car;
> 
> Which can be read "My new Saab is a Car".

The project I worked on that banned "_Type" also tried to encourage
developers to choose identifiers that make a complete grammatically
correct english sentence, as if it were more important that
non-technical folks could read the code than the maintainers.  

It didn't work out too well, because when you make an english sentence
in one usage, the same identifers make the code look like crap where
an english sentence doesn't exist.  ie.

   function compute_altitude (using : in temperature;
                              and   : in dew_point;
                              with  : in pressure) return altitude is
   begin

      return (using + and / with);

   end compute_altitude;

Obviously that's a bogus formula.. but it should be clear from this
that making code read like english down to the point of including
articles like "and", "with", "is", asks for disaster.  Some folks
really complied with this direction, and wrote code like that function
above - I'm not joking.