Re: Some suggestions on coding style - a chance to critique

[moxliukas]

I'm a beginner at Perl too, so I'm not sure if my suggestions are quite relevant. However, I was surprised to see this sort of code:

my $redirect = "http://www.yoursite.com"; 
my $sendmail = "/usr/sbin/sendmail"; 
my $subject = "Form Submission Results";

I have always thought that I should avoid double quoted strings in expressions like these, because they take longer to parse (Perl has to do various substitutions, right?). So I would use single quoted strings in these examples. Please correct me if I am wrong, as I would be interested to read some discussion about this.

[staunch]

$ perl -MO=Deparse
my $redirect = "http://www.yoursite.com"; 
my $sendmail = "/usr/sbin/sendmail"; 
my $subject = "Form Submission Results";  

my $redirect = 'http://www.yoursite.com';
my $sendmail = '/usr/sbin/sendmail';
my $subject = 'Form Submission Results';
- syntax OK

I believe this is optimized away, so I think it really is only a matter of preference. I personally prefer to use single quotes when possible though.


Staunch

[emilford]

You're right! I looked at this post and they mentioned using single quotes when no interpolation of variables is needed. They also mentioned that this is a matter of personal preference. This probably would be good practice, but in my use, I'm not sure if it makes that big a difference. I wonder how much of a time difference single quotes vs. double quotes makes? Either way, thanks for the suggestion.

[thelenm]

Running this code:

use Benchmark qw(cmpthese);
cmpthese(10000000, {
  single => sub {$foo = 'http://www.yoursite.com'},
  double => sub {$foo = "http://www.yoursite.com"},
});

produces these results on my machine:

            Rate double single
double 2865330/s     --    -2%
single 2915452/s     2%     --

So it looks like single quotes may be slightly faster, but that may be within the margin of error. I generally use single quotes unless I need interpolation of variables, but it's probably just a matter of preference.

-- Mike

--
just,my${.02}