Re: Ada Idioms Progress Preview

[Kilgallen@eisner.decus.org.nospam (Larry Kilgallen)]

In article <3_Xc7.45$NM5.84779@news.pacbell.net>, "Jay Nabonne" <jay@rightagain.com> writes:

> As a C/C++ programmer who is looking with interest at Ada (after a rather
> entertaining discussion about Code Red in comp.lang.c++), what would be most
> useful for me - and it's what I thought of when I saw the word idiom - is
> something that says "in order to do <blah>, given that there's more than one
> way to do it within the Ada language, here's how you write code that looks
> like an Ada programmer wrote it and doesn't look like a
> C++-programmer-writing-Ada wrote it.".
> 
> I'm interested in how to "think in Ada"...

The criterion for success is that someone reading your code cannot tell
whether your background is C or Fortran.  (Or anything else, but the
original statement, so far as I can tell, is "It is possible to write
Fortran in any language".)

WWW.AdaPower.com should have an item on "Ada for C programmers" that
gives some ideas of the ways "not" to do it.  Perhaps one technique
for those whose background is Csomething is to think very hard in
an Ada program before taking the address of something.  Generally
it is not necessary, but there is a tendency to do it if C is on
your mind.  Another trick might be not to assume you can guess what
the machine code is going to look like.  Passing a record as a
parameter is _not_ less efficient than passing a pointer, since
what Ada does under the covers is typically a pointer.

Of course things that don't involve instruction-level efficiencies
are no different -- if you read every block on the disk it will still
take a while, so higher level program efficiency rules still count.