$ARGV dilemma

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

Fellow monks, I am having a problem using $ARGV as I intend, here is the problem:

I am trying to force that 3 mandatory arguments are included at execution. for example:

die "Usage: $0 [arg] [arg] [arg]\n" 
unless ($ARGV[0], $ARGV[1], $ARGV[2]);
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However, this doesn't work... Any ideas what will?

Comment on $ARGV dilemma Download Code

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Re: $ARGV dilemma
by blue_cowdawg (Monsignor) on May 27, 2001 at 15:42 UTC

Check out the following:

--$  cat argvtest.pl 
#!/usr/bin/perl -w 
###################################################################
use strict;

print "too few$/" if scalar(@ARGV) < 3 ;
print "just right$/" if scalar(@ARGV) == 3;
print "too many$/" if scalar(@ARGV) > 3;
--$  perl argvtest.pl 1 2
too few
--$  perl argvtest.pl 1 2 3
just right
--$  perl argvtest.pl 1 2 3 4
too many
--$
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scalar is your friend! ;-)
HTH

Peter L. Berghold	Schooner Technology Consulting, Inc.
Peter@Berghold.Net	www.berghold.net

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Re: Re: $ARGV dilemma

by blakem (Monsignor) on May 27, 2001 at 16:47 UTC

print "too few$/" if scalar(@ARGV) < 3;
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print "too few$/" if @ARGV < 3;
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Re: Re: Re: $ARGV dilemma

by blue_cowdawg (Monsignor) on May 27, 2001 at 16:52 UTC

While I can't show you an example: I have seen numeric comparisons not work. Wish I could remember where it happened but it was a while ago...

Peter L. Berghold	Schooner Technology Consulting, Inc.
Peter@Berghold.Net	www.berghold.net

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Re: $ARGV dilemma
by dusk (Friar) on May 27, 2001 at 06:11 UTC

UPDATE:

unless $ARGV[2]

UPDATE 2: I guess I should have been more precise in both my question and update. Originally, the last argument was 0; but changing it to a string was the solution I came up with..

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Re: Re: $ARGV dilemma

by dws (Chancellor) on May 27, 2001 at 07:42 UTC

unless $ARGV[2]

unless defined $ARGV[2]

if 3 > @ARGV

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Re: Re: $ARGV dilemma

by wog (Curate) on May 27, 2001 at 07:41 UTC

What if @ARGV = ("0","0","0"). Then $ARGV[2] is false and you get an error despite having three arguments.

You probably like something like unless @ARGV == 3.

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