ISO Studies of underscores vs MixedCase in Ada or C++

[Andy Glew]

I am in search of any rigourous,
scientific, academic or industrial studies
comparing naming conventions in
C++ or similar languages such as
Ada:

Specifically, are names formed with
underscores more or less readable
than names formed with MixedCase
StudlyCaps camelCase?

....and similarly, any measurements
of programmer productivity, bug rate,
etc.; although IMHO readability matters
most.
* Religion - NOT?!

I understand that this is a religious issue
for many programmers, an issue of programming style.
I am not interested in a religious war.
I obviously have my own opinion, but I am
open to scientific evidence.
* Ada Studies?

I thought that I had seen studies like
this in some of the early design documents
for Ada, but I have not been able to find
such references on the web. Which is not
entirely surprising, since Ada was designed
prior to the web.

The Ada 83 and 95 Quality Guidelines recommend
underscores to improve readability, but provide
no source justifying this statement.
* What such studies might look like

Simple readability and recall:
- present a test subject with
a list of compound words
formed with underscoresand mixed case
- remove the list, and ask test subject
to write it
- score on accuracy

Program debugging
- present programs that are otherwise identical,
differing only in their use of underscores/MixedCase
to test subject programmers (e.g. a CS class)
- program has a known bug
- ask test subjects to find bug
- score on accuracy locating bug

Cruel TA study:
- Two sections of a CS class
- Enforce programming standards,
underscores vs MixedCase
- Pose a programming problem
- Score according to success
completing assignment

Empirical:
- Given version control databases
of large programs, some written in underscore
style, others in MixedCase
- Total bug rates normalized by LOC, name count, etc.
- OR: count only bugs that can be attributed
(after inspection of checkins) to misnamed variables

For that matter, I would be interested in any surveys
folks may have done that count projects and their
coding standards, possibly weighted
- open source (e.g. sourceforge)
- industrial
- textbooks, weighted by sales
- websites of coding standards, weighted by Google score...
Although this is less convincing than a rigorous study.
* Explanation of Newsgroups Chosen

I hope it is obvious why I have chosen these
newsgroups to post this search to:

comp.software-eng, comp.programmin g,
- an issue of software engineering
comp.lang.c++,
- the language I am most interested in
comp.lang.ada
- because I vaguely recall historical work

[Attila Feher]

Andy Glew wrote:

I am in search of any rigourous,
scientific, academic or industrial studies
comparing naming conventions in
C++ or similar languages such as

[SNIP]

The underscore convention work also in case insensitive languages.

The InnerCaps convention fails to solve the issue of all caps words like
SMTPTCPIPConnec tion. Usual solution is to write them wrong as
SmtpTcpIpConnec tion.

The underscore convention tends to make lines longer, which can have bad
effect on readablity.

IMO it is a personal preference issue, and also an issue of what fonts and
development envirnmoent is in use.

IMO if one has to select *one* convention for a whole company using many
languages then only the underscore one stands. With InnerCaps there is a
possibility to create hard-to-find name collisions, especially in languages
where the type of variables can change runtime by a simple assignment.

--
Attila aka WW

[Jakob Bieling]

"Andy Glew" <an*******@amd. com> wrote in message
news:2c******** *************** ***@posting.goo gle.com...

[snip]

Specifically, are names formed with
underscores more or less readable
than names formed with MixedCase
StudlyCaps camelCase?
Write a large text (several lines) with mixed-case and the same again
with underscores. Then give it people to read and ask them what they find
easier to read. I would not be surprised if the majority favours the text
with underscores.

[snip]
The Ada 83 and 95 Quality Guidelines recommend
underscores to improve readability, but provide
no source justifying this statement.

The underscore can easily be view as a space which seperates the words,
whereas mixed-case does not provide a seperation like that, but rather a
'large' here-comes-a-new-word-mark (ie. the captial letter). The problem I
see with this: non-captial letters can be 'large' as well. just have a look
at the 't', 'h' etc, which, imo, does not make reading a mixed-case text
easier.

Personally, I prefer underscore for the reason above.

Just my .02c
--
jb

(replace y with x if you want to reply by e-mail)

[Matt Gregory]

Jakob Bieling wrote:

The underscore can easily be view as a space which seperates the words,
whereas mixed-case does not provide a seperation like that, but rather a
'large' here-comes-a-new-word-mark (ie. the captial letter). The problem I
see with this: non-captial letters can be 'large' as well. just have a look
at the 't', 'h' etc, which, imo, does not make reading a mixed-case text
easier.

I think we just need a programming font that has half-sized underscores
in front of all the capital letters. That would solve all these problems.
I personally don't like typing underscores, but I agree they are more
readable. Emacs does have a view-camel-cased-identifiers-as-underscored
mode, so that's a step in the right direction.

[Ludovic Brenta]

Personally I prefer underscores, too, and for that reason I really
like Emacs' glasses-mode. So, use whatever you want, *I* will always
see underscores :)

--
Ludovic Brenta.

[Steve]

I think a more relevent test would be to give two versions the same code,
one with underscores, one with mixed casing, to different groups of
programmers to analyze. Include a quiz asking questions about the code.
See which version results in more correct answers, and which version
achieves the answers more quickly.

Steve
(The Duck)

"Jakob Bieling" <ne*****@gmy.ne t> wrote in message
news:bl******** *****@news.t-online.com...
[snip]

Write a large text (several lines) with mixed-case and the same again
with underscores. Then give it people to read and ask them what they find
easier to read. I would not be surprised if the majority favours the text
with underscores.

[Frank J. Lhota]

Underscores are basically a way to provide spaces in an identifier. Since
identifiers are generally phrases (nown phrases for objects, verb phrases
for procedures) and phrases often consist of more than one word, I find the
use of underscores to be quite natural.

The opposing argument is that underscores are too large, and that a case
change is a more readable way to indicate how to divide the decomposition
into words. To me, the upper / lower case method of delineate the words in
an indentifier has always looked like the transcript of a very fast talker.
Yes, you can make out the words, but just barely. Moreover, the use of
letter case to delineate words prohibits any other use of letter case. It
rules out using all caps for a certain category of identifiers, for example.

There is an easy way to test which convention is more readable. Here is one
of Shakespeare's sonnets rendered in the mixed case format:

FromFairestCrea turesWeDesireIn crease,
ThatTherebyBeau tysRoseMightNev erDie,
ButAsTheRiperSh ouldByTimeDecea se,
HisTenderHeirMi ghtBearHisMemor y:
ButThouContract edToThineOwnBri ghtEyes,
FeedstThyLights FlameWithSelfSu bstantialFuel,
MakingAFamineWh ereAbundanceLie s,
ThySelfThyFoeTo ThySweetSelfToo Cruel:
ThouThatArtNowT heWorldsFreshOr nament,
AndOnlyHeraldTo TheGaudySpring,
WithinThineOwnB udBuriestThyCon tent,
AndTenderChurlM akstWasteInNigg arding:
PityTheWorldOrE lseThisGluttonB e,
ToEatTheWorldsD ueByTheGraveAnd Thee

It may be a matter of taste, but I certainly found the original sonnet to be
more readable and more beautiful.

[Randy King]

<snip> op <snip>

This is a somwhat offtopic post, but the OP did ask the question about
readability.

Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer
inwaht orredr the ltteers in a wrod are, the olny iprmoetnt tihng is
taht the frist and lsat ltteer be at the rghit pclae. The rset can be a
total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae
the huamn mnid deos not raed ervey lteter by istlef, butthe wrod as a
wlohe. Aolbsulty amzanig huh?

[Hyman Rosen]

Randy King wrote:

Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer
inwaht orredr the ltteers in a wrod are, the olny iprmoetnt tihng is
taht the frist and lsat ltteer be at the rghit pclae. The rset can be a
total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae
the huamn mnid deos not raed ervey lteter by istlef, butthe wrod as a
wlohe. Aolbsulty amzanig huh?

"Anidroccg to crad cniyrrag lcitsiugnis planoissefors at an uemannd,
utisreviny in Bsitirh Cibmuloa, and crartnoy to the duoibus cmials
of the ueticnd rcraeseh, a slpmie, macinahcel ioisrevnn of ianretnl
cretcarahs araepps sneiciffut to csufnoe the eadyrevy oekoolnr."

[Matt Gregory]

I wrote:

I think we just need a programming font that has half-sized underscores
in front of all the capital letters. That would solve all these problems.

Nevermind, that was a terrible idea. It was almost good though.