|
•Re: Plural variable naming (or not?)
by merlyn (Sage) on Mar 19, 2002 at 14:46 UTC
|
I support $singular and @plurals as a general convention. However,
for hashes, I tend to think of hashes as providing a mapping function between a
key and its value, so I frequently name it as a f() style, as in %last_name_for or %last_name_of or %has_subentries. That makes it clear to the reader that I'm holding a mapping in that hash.
-- Randal L. Schwartz, Perl hacker | [reply] |
|
|
For the $singular and @plurals, I had independently come to Randal's style. I haven't used his style for hashes, but it looks good and I am going to try it.
| [reply] |
|
|
Only a mere 14 years later!
-- Randal L. Schwartz, Perl hacker
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.
| [reply] |
|
|
Re: Plural variable naming (or not?)
by tachyon (Chancellor) on Mar 19, 2002 at 14:57 UTC
|
The rules for variable naming are based on (in no particular order ;-)
- Company policy
- Project policy
- Immediate bosses policy
- Personal preference
- Language Norms
- Logic $scalar @arrays %hash(s) FILEHANDLE &increment_widget_value
One word: ->Consistency<-
There_is_nothing
worseThan
code_that
DoesNotUse
CONSISTENT_nAmInG_CoNvEnTiOnS.
cheers
tachyon
s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print
| [reply] |
Re: Plural variable naming (or not?)
by Juerd (Abbot) on Mar 19, 2002 at 12:27 UTC
|
As usual, it's a matter of style :)
My style is:
$singular
@plural
%singular
With one exception: I often have %subs, a hash that contains sub references. For some reason, I have always put that in plural.
A good document on style is slashstyle (Note: I don't agree on many points, but it's nice to read, and gives an indication of the many possibilities.)
U28geW91IGNhbiBhbGwgcm90MTMgY
W5kIHBhY2soKS4gQnV0IGRvIHlvdS
ByZWNvZ25pc2UgQmFzZTY0IHdoZW4
geW91IHNlZSBpdD8gIC0tIEp1ZXJk
| [reply]
[d/l] |
|
|
It is not merely a matter of style. It is also a matter of program context, and wheter or not the name is more ambigious with the plural (or singular (thanks for freshing up the mind)) and may not provide as much context as could be intended.
Therefor a programmer expecting to have his code reviewed or updated should be well considering the use of plural or singular form on each variable name, and the matter of style should be thrown overboard on this specifick isue... (Or should it not...?!?)
er formait hyarya.
"Field experience is something you don't
get until just after you need it."
| [reply] |
Re: Plural variable naming (or not?)
by ChOas (Curate) on Mar 19, 2002 at 11:15 UTC
|
Hi!,
I have have often thought about the same thing, and now I only use non plurals (sorry, lack of English)
One question:
If you wish to apply the entire list (eg: foreach (@fields) { ... })
You must name you array @fields.
I`m not sure why you say that...
I think there is nothing wrong with saying "for each field do yadayadayada"
e.g foreach(@field)
Nice to know I`m not the only one thinking about all that stuff :)
GreetZ!,
print "profeth still\n" if /bird|devil/; | [reply]
[d/l]
[select] |
|
|
foreach my $field (@fields)
Assuming of course you don't want to just stick with $_ :)
| [reply]
[d/l] |
Re: Plural variable naming (or not?)
by andreychek (Parson) on Mar 19, 2002 at 18:15 UTC
|
I have really come to enjoy the ideas and syntax offered by the P5EE Style Guide.
In the guide, they offer this for plural vs singular variable naming conventions:
---
Arrays and hashes should be plural nouns, whether as
regular arrays and hashes or array and hash references. Do
not name references with ``ref'' or the data type in the
name.
@stories = (1, 2, 3); # right
$comment_ref = [4, 5, 6]; # wrong
$comments = [4, 5, 6]; # right
$comment = $comments->[0]; # right
---
By consistantly using a system like this throughout your programs, there won't have to be question about whether a scalar contains something like a string, or if it's a reference to an array or hash. As the guide suggests, references would be named in a plural fashion.
FWIW, I'm now using (or at least attempting to) this guide for all of my programming habits :-) Have fun,
-Eric
| [reply]
[d/l] |
|
|
By consistantly using a system like this throughout your programs, there won't have to be question about whether a scalar contains something like a string, or if it's a reference to an array or hash.
7 years later, I have this to say ….
It seems to me that this offers exactly the benefit you describe, but that that benefit might not be what it seems at first glance. That is, I can tell by looking at a variable name * whether it is
- a string,
or - a reference to an array or hash;
but I cannot answer the question of whether it is
- a string,
- a reference to a string,
- a reference to an array,
or - a reference to a hash.
(For that matter, there are all sorts of other references (and, for that matter, other things to stuff in scalars, like numbers), too, like \\1.) It seems to me that this is a level of granularity that one would like, in many cases, to be able to maintain. I don't know a better solution than the pseudo-Hungarian $ima_href, though, and I don't think much of that.
* Although it's important to note that I can't even necessarily do that—is $moose singular or plural?
| [reply]
[d/l]
[select] |
Re: Plural variable naming (or not?)
by FoxtrotUniform (Prior) on Mar 19, 2002 at 16:35 UTC
|
Like most people here, I usually name $singular,
@plural. My hashes are singular if they represent a
data structure, and plural if they represent a
mapping.
One exception to the first rule, though, is that
I'm perfectly happy to name a scalar in the plural...
if it's an arrayref or an appropriate hashref.
--
:wq
| [reply] |
Re: Plural variable naming (or not?)
by cjf (Parson) on Mar 19, 2002 at 14:53 UTC
|
I follow naming conventions roughly similar Juerd and simon.proctor.
Scalars should be singular, it really throws me off when they're not, $fields just really doesn't look right. Arrays should always be plural. Hashes on the other hand, I'm fairly indifferent about, but I tend to lean towards singular $field{name}. I think this looks a bit better than $fields{name} but it does depend somewhat on what it's being used for.
| [reply]
[d/l]
[select] |
|
|
my @replies = ( 'so', 'plurals', { 'you' => 'think?' } );
my $answer = $replies[2]->{you};
print $answer;
| [reply]
[d/l] |
|
|
Actually, yes, it does :)
It might only appear right to me because I've become accustomed to doing it that way. I do see your point, but I still find plural array names feel more natural than singular ones:
my @reply = qw/a singular array name? how odd/;
my $cannotnamethisreply = $reply[5];
print $cannotnamethisreply;
Now that looks stranger to me than using a plural for the array name and a singular for the related scalar. I can understand either view though. :) | [reply]
[d/l] |
|
|
$fields = [1, 2, 3];
That also helps me to remember that it's not a "normal" scalar, but that it's really referring to something plural. | [reply]
[d/l] |
Re: Plural variable naming (or not?)
by beppu (Hermit) on Mar 20, 2002 at 02:55 UTC
|
Am I the only one who uses the singular form for arrays? | [reply] |
|
|
No, you aren't:
Some names (i often name variables in german, or mix the
languages, this i should change!):
@mathsylist : a name for a list in that i store the recent mathsymbols.
%preprintliste : the matching preprints, stored as a hash,
in order to avoid trouble with doubleentries in two files.
@sortierteschluessel: this is plural (sorted keys) for exactly that.
It seems that i either use plural or something like list in
the end.
| [reply] |
|
|
Interesting... I'd have thought that @plural would
be more intuitive than @singular_list. Obviously,
your mileage varies.
The one place I can see where this would be a
distinct advantage is when you're using Perl arrays
as different data types. For instance:
my @foo_list;
my @bar_stack;
my @baz_queue;
my @xyzzy_heap;
If these were just plurals, it would be impossible
to tell just from the names which one was a stack, or
a queue, or whatever -- which could be a very bad
thing.
--
:wq
| [reply]
[d/l] |
Re: Plural variable naming (or not?)
by JavaFan (Canon) on Dec 11, 2009 at 10:08 UTC
|
use Data::Alias;
my @plural = qw[foo bar baz];
alias my @singular = @plural;
say $singular[1];
$singular[2] = "qux";
say "@plural";
__END__
bar
foo bar qux
| [reply]
[d/l] |
|
|
Hi,
Let's keep this oldies but interesting post running. :)
PERL has a point in using singular even for arrays. That is the sigil. Saying @persons is superfluous, @ marks it's a list (an array) of something. $car[3] could be read for example as 'Third car in the array' or 'Car number three in the array'.
Square brackets will reveal if it's an array if in doubt. Consistency is important. Perlstyle could give some advice also in this matter.
Beers, T
| [reply]
[d/l]
[select] |