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Perl Getopt::Long question - stopping multiple args


 
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# 1  
Old 02-17-2010
Perl Getopt::Long question - stopping multiple args

Hi there, I have an example basic script (below) and ive been trying to figure out how to stop multiple arguments to my options occuring. for example using the example script below I can issue two arguments for, say the --surname option and it will not barf at me (although thats what i want it to do). It just ignores the second argument to the --surname option completely and happily continues.

Code:
#./name.pl --firstname John --surname Smith Jones
firstname is set to  - John
surname is set to  - Smith

How would i get it to barf at me for providing too many options ?

Any help would be great



The Script

Code:
#!/bin/perl

use strict;
use Getopt::Long;

my $firstname = "";
my $surname = "";
my $help = "";

GetOptions (
                "firstname=s"           => \$firstname,
                "surname=s"             => \$surname,
                "help!"                 => \$help,

                ) or die "Incorrect usage.\n";


if( $help )
{
        print "Common on, it's really not that hard.\n";
} else {



        if (!$firstname) { print "You have failed to enter a --firstname value\n"; exit 11 }
        if (!$surname) { print "You have failed to enter a --surname value\n"; exit 12 }


        print "firstname is set to  - $firstname\n";
        print "surname is set to  - $surname\n";

}

# 2  
Old 02-17-2010
Getopt::Long won't stop on any usage that isn't explicitly forbidden by it's internals. One way would be to allow multiple values for Getopt::Long, and throw an error yourself if the resulting array contains more than 1 value.

---------- Post updated at 14:55 ---------- Previous update was at 14:53 ----------

Or define your own subroutine handler for that option.
# 3  
Old 02-17-2010
Thanks Pludi, Ive been playing around and i wonder if you could help me clarify something. I changed the relevant lines (bolded in red below) to make surname an array (which looks like it creates a reference to the array). but it still seems to print only the one argument ?

Am i missing something here? Will a scalar reference to an array always only return the first object in an array ? apologies if ive done something dumb here

Code:
#!/bin/perl
use strict;
use Getopt::Long;

my $firstname = "";
my $surname = "";
my $help = "";

GetOptions (
                "firstname=s"           => \$firstname,
                "surname=s@"             => \$surname,
                "help!"                 => \$help,

                ) or die "Incorrect usage.\n";

if( $help )
{
        print "Common on, it's really not that hard.\n";
} else {

        print "firstname is set to  - @$firstname\n";
        print "surname is set to  - $surname\n";

}

As you can see its still the same

Code:
# ./name.pl --firstname John --surname smith jones    
firstname is set to  - John
surname is set to  - smith

I tried it using this as well
Code:
"surname=s"             => \@surname

...
...

print "surname is set to  - @surname\n";

with the same output, so maybe its not just an issue with references
# 4  
Old 02-17-2010
Good thing they provide an example with the documentation.
Code:
#!/bin/perl
use strict;
use Getopt::Long;

my $firstname = "";
my @surname   = ();
my $help      = "";

GetOptions(
    "firstname=s" => \$firstname,
    "surname=s@"  => \@surname,
    "help!"       => \$help,

) or die "Incorrect usage.\n";

if ($help) {
    print "Common on, it's really not that hard.\n";
}
else {

    print "firstname is set to  - $firstname\n";
    print "surname is set to  - @surname\n";

}

Code:
$ perl getopt.pl --firstname John --surname Smith --surname Jones
firstname is set to  - John
surname is set to  - Smith Jones

# 5  
Old 02-17-2010
Sorry Pludi, i think you may have misunderstood my problem, issuing multiple --surnames is not really the problem, its when they issue multiple arguments to the same --surname option

using the exact script you posted above, i issued

Code:
 # ./name.pl --firstname john --surname smith jones
firstname is set to  - john
surname is set to  - smith

wjen we print the array at the bottom of the script, the second argument is not printed
# 6  
Old 02-17-2010
Ah, you mean like the example a few paragraphs down in the documentation?
Code:
#!/bin/perl
use strict;
use Getopt::Long;

my $firstname = "";
my @surname   = ();
my $help      = "";

GetOptions(
    "firstname=s"   => \$firstname,
    "surname=s{1,}" => \@surname,
    "help!"         => \$help,

) or die "Incorrect usage.\n";

if ($help) {
    print "Common on, it's really not that hard.\n";
}
else {

    print "firstname is set to  - $firstname\n";
    print "surname is set to  - @surname\n";

}

Code:
$ perl getopt.pl --firstname John --surname Smith Jones
firstname is set to  - John
surname is set to  - Smith Jones

# 7  
Old 02-18-2010
Pludi, I apologise. I must have read through that documentaion 3 times but seem to have been overwhelmed by the information and missed the paragraph that i needed... Thank you for your help

---------- Post updated at 11:12 AM ---------- Previous update was at 06:14 AM ----------

Bah, would you believe it the "option=s{'1,}" functionality is only available in 5.10 by the looks of it, all my systems are perl 5.8 or less .

I get this error when running the script on 5.8 or below

Code:
# ./name.pl  
Error in option spec: "surname=s{1,}"

Smilie oh well

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