Re: Side-effect arithmetic again [was: Ada ... in embedded systems]

[geert@fozzie.sun3.iaf.nl (Geert Bosch)]

Robert I. Eachus (eachus@spectre.mitre.org) wrote:
:     (Should the function form be named something other than Inc and
: Dec?  Does the Ada domain specific knowledge that the parameters of
: a function are not changed dominate here, or should it be named Next?)

The terms increment and decrement suggest an update of the parameter, so
I think these terms are good. Something like Next(T) sounds more like a
function. Also when speaking about these operations everybody talks about
incrementing and decrementing variables, so I see no justification for using
other terms.

One point would be whether to use the long or the short name. I'd vote for
the long version. I don't see the huge win in saving those 6 keystrokes. 
I find that I can read the word Decrement as fast as Dec. For people who are 
not guilty of having used assembly-language the long variant will definately 
be easier to understand.  So, I think the best readable variant is to use 
Increment and Decrement.

When I helped people with their initial programming course (using Turbo
Pascal) I found that for most people Inc(x) and Dec(x) were not clear:
they often asked what those functions did or looked them up in the
library. Once they knew the new secret function they used it all over
the place, because Inc(A[I]) would be much faster than A[I] := A[I] + 1;
Most of them were very disappointed when I showed them that both forms
generated identical code. There must be some reason that people want to
write Inc(I); or I++; instead of I := I + 1; or Increment(I); 

BTW: I really, really  miss those mixed assembly/Pascal listings in
which the assembly used the right symbolic names for both globals and
locals.

Greetings,
   Geert

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