Re: IDENTIFIERS in Upper Case

[dewar@merv.cs.nyu.edu (Robert Dewar)]

iMatthew quotes

<<In Guidelines for Enterprise-Wide GUI Design, authors Susan Weinschenk and
Sarah C. Yeo state that "Sentances in all capital letters are 20 percent
more difficult to read than sentences with upper- and lower-case letters.
Avoid using all caps for large blocks of text." [p. 101]  They later state,
when discussing online help, that one should "Never use all caps, except
for acronyms and initializations.  Words in all caps are harder to read."
[p. 144]>>

I believe that this observation is totally irrelevant to programming
languages. Furthermore, I am not sure it is true even for the environment
that Sarah is talking about. I believe the 20% figure if you are talking
about the difficulty that people have in reading upper case if they are
used to reading normal lower case, but I bet if you tool a control group
of children and reversed the way they were taught that you would see the
20% in the opposite direction.

In the case of programming languages, we ARE talking about people who
are very much used to whatever style they are reading. My guess is that
if you use only people who are very used to reading the style that they
are presented with, you will not see measurable differences. The trouble
is in getting really comparable groups.

When I first started to read Ada code written in mixed-case I found it
MUCH harder to read than the all-upper-case identifier code that I was
used to (at the time I wrote most of my Ada code for Alsys, and that was
our internal convention at the time).

However, now it is exactly the opposite way round for me.

That's why I think it is important that everyone learn to be comfortable
with the same style. The particular choice of style is pretty unimportant.
There are very few objective arguments that favor one style over another,
for a discussion of these see our previous CLA thread on the the subject,
but I think these points are minor compared to the annoyances tha result
from people trying to interact who have different styles.

One of the advantages in C, is that there was a uniform style in C (I
never saw anyone for instance using all upper case identifiers in C
for all purposes, though of course this is perfectly legal in C).

In the Ada 95 world, the use of mixed case identifiers and lower case
keywords is almost universal (I am making that judgment from the code we
have received from thousands of Ada programmers who have sent us code
samples). Yes there are a few variations (probably the majority come
from students influenced by Mike Feldman's "non-standard style" -- that
certainly accounts for at least 50% of the variations -- some of the
rest are old Ada 83 programs written under influence of the implied
recomendations of the old RM (all upper case identifiers).

Since we nearly have a standard in effect, I think the best choice is
to follow that standard and use lower case keywords and mixed case
identifiers. This is one situation where, like driving on one side of
the road, it is more important to have consistency in the community
than to make any one particular choice.

Yes, it can be painful to change over, it certainly was for me, it took
quite a while before I could read mixed case stuff as reliably as the
all upper case identifier style I was used to, but the change over is
worth while (just as Sweden found it was worth while changing to driving
on the right :-)