On Friday 05 May 2006 12:29, Steve Swift wrote:
> I've written a tiny program to make it easy to test the syntax and
> effects of a Perl statement. My program is called "perltry" and here it
> is in its full gory (pun intended)
>
> #!/usr/bin/perl
> use strict;
> use warnings;
> system('clear');
> system('perl -v');
> print "Go on - try a few... Enter 'exit' to end.\n";
> while (<>) {
> eval $_;
> if ($@) {print "[EMAIL PROTECTED]";}
> print ' ','.'x50," perltry on $^O\n"
> };
>
> If I enter a statement, such as "$a=1;" (without the quotes) then I
my $a = 1;
> would expect that scalar $a would get the value 1. If I then enter the
> statement "print $a" I expected to see "1". What I saw was:
> Use of uninitialized value in string at (eval 2) line 1, <> line 2.
This is because the scope of the variable $a is only within the block. You
might try using 'our' instead of 'my', but I'm also a beginner so I don't
know the meanings of 'our'.
> Could someone tell me why this happened, please?
> Is it possible to change this so that the variable $a would get set?
You might also use perl in oneliner-mode:
perl -w -e '$a=1;print "$a\n";'
See also the -n and -p parameters.
> This is my very first post to a Perl newsgroup, so treat me gently, please!
Welcome!
--
Bjørge Solli - Office:+47 55205847 http://www.nersc.no
Nansen Environmental and Remote Sensing Center - Bergen, Norway
Dept.: Mohn-Sverdrup Center for Global Ocean Studies
and Operational Oceanography
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