Boundary conditions with Getopt::Std

blink has asked for the wisdom of the Perl Monks concerning the following question:

Given the following:

use vars qw /%option/;

getopt('m:f:l:s:q:h', \%option);
[download]

how do you test for "no command line options specified" if each key in %option equals 1 by default?

Another related question: I'm trying to say "if you use this option, it needs to accompany another option", and I just realized that what I'm doing doesn't work as expected. Here's what I have:

if ($option{f})
{

    die
      "You must use the -f option along with another option\nRun $0 -h
+ to view all available options\n"
      unless (($option{f}) && ($option{l} || $option{m} || $option{d})
+);
    $ctlFile = "$option{f}";
}
[download]

TIA,
--s

Comment on Boundary conditions with Getopt::Std Select or Download Code

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Re: Boundary conditions with Getopt::Std by Abigail-II (Bishop) on Jan 30, 2004 at 16:28 UTC
If no command line options where specified, `%option` will be empty. The value of 1 is set if the option is present, but the option doesn't have an argument. (At least, that's what the documentation says, some trivial testing suggests that if no argument is given, `undef` will be used). As for your second question, I'd use `exist` to check whether an option is set, or else you might get tripped by the fact that the option is used, but the argument is false. Abigail	[reply]
Re: Boundary conditions with Getopt::Std by Limbic~Region (Chancellor) on Jan 30, 2004 at 16:25 UTC
blink, I know it can be confusing, but I think you want getopts from Getopt::Std instead. Here is a fully functional template for you. `#!/usr/bin/perl -w use strict; use Getopt::Std; my %Opt; Get_Args(); sub Get_Args { my $Usage = qq{Usage: $0 [options] -h : This help message. -a : BOGUS - requires argument if used -A : BOGUS -b : BOGUS } . "\n"; getopts( 'ha:Ab' , \%Opt ) or die $Usage; die $Usage if $Opt{h}; die "You did not enter any options\n" if ! %Opt; if ( exists $opt{a} \|\| exists $opt{A} ) { if ( ! ( exists $opt{a} && exists $opt{A} ) ) { die "You must use -a and -A together\n"; } } }` [download] Cheers - L~R	[reply] [d/l]
Re: Boundary conditions with Getopt::Std by duff (Parson) on Jan 30, 2004 at 16:27 UTC
how do you test for "no command line options specified" if each key in %option equals 1 by default? They only equal 1 if the option is specified. For those options that take a value, you either get 1 or the value specified on the command line. Another related question: I'm trying to say "if you use this option, it needs to accompany another option", `unless ($option{f} && $option{h}) { die "If you use -f, you must also use -h, and vice versa."; }` [download] Assuming I understand you correctly. Or if you wanted the relation to be one-way (i.e., -f needs to accompany -h, but -h doesn't need to accompany -f) then you could do something like this: `if ($option{f} && !$option{h}) { die "If you use -f, you must also use -h"; } if ($option{h}) { ... }` [download] duff	[reply] [d/l] [select]