Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic
 
PerlMonks  

Re: Little annoying mistakes ... of others

by Limbic~Region (Chancellor)
on Dec 06, 2008 at 22:34 UTC ( #728606=note: print w/ replies, xml ) Need Help??


in reply to Little annoying mistakes ... of others

szabgab,
I am sure I could come up with a laundry list but my mind is on other things (family isn't feeling well). The one that bugs me is not considering defined values that evaluate to false when setting up a conditional. Since I am guilty of this, let me give an example:

#!/usr/bin/perl use strict; use warnings; my $file = $ARGV[0] or die "Usage: $0 <input_file>"; open(my $fh, '<', $file) or die "Unable to open '$file' for reading: $ +!";

While I think it is uncommon that someone would name their file '0', it is possible. In other examples, the oversight might be the empty string ''. As a reference, see True and False (aka Booleans). I know that 5.10 introduced the // operator which is great.

Cheers - L~R


Comment on Re: Little annoying mistakes ... of others
Download Code
Re^2: Little annoying mistakes ... of others
by toolic (Chancellor) on Dec 07, 2008 at 02:59 UTC
    Along the sames lines, and much more likely, is to pass in a numeric option on the command line whose value is quite probably 0. For example, I have a histogram script in which I can pass in the minimum value. Unless I check the value using defined, the thing just doesn't work right:
    use strict; use warnings; use Getopt::Std; our $opt_m; getopts('m:'); print "$opt_m\n" if ($opt_m); # Wrong #print "$opt_m\n" if (defined $opt_m); # Right

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://728606]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others contemplating the Monastery: (7)
As of 2014-12-18 01:01 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    Is guessing a good strategy for surviving in the IT business?





    Results (41 votes), past polls