merlyn may want to use a map() function, but a *really* good function handles scalars or arrays as inputs. To that end, here is an example that runs all the test cases I could think of. 
#!/usr/local/bin/perl -w

use strict;

{
   test1 ();
   test2 ();
   test3 ();
   test4 ();
}

#
#  Uses a simple scalar
#
sub test1
{
   my $i = "Hello, World";

   print "return - '", remove_caps ($i), "', \$i ='$i'\n";
}

#
#  Simple scalar, result is set to a different variable
#
sub test2
{
   my $i = "Hello, World";

   my $o = remove_caps ($i);

   print "return - \$i='$i', \$o='$o'\n";
}

#
#  Pass a constant
#
sub test3
{
   print "constant - ", remove_caps ("Hello, World"), "\n";
}

#
#  Operate on an array
#
sub test4
{
   my @iarray = ('Hello, World', 'Goodbye, Cruel World', 'Britney Spea
+rs Sux');

   my @oarray = remove_caps (@iarray);

   print "iarray = ";  print "'$_', " foreach (@iarray); print "\n";
   print "oarray = ";  print "'$_', " foreach (@oarray); print "\n";
}

#
#  Our humble little function
#
sub remove_caps
{
   my @out = @_;

   tr/A-Z//d for (@out); 

   return wantarray ? @out : $out[0];
}

[download]
--Chris

e-mail jcwren

In reply to (jcwren) RE: modify variable on pass by value by jcwren
in thread modify variable on pass by value by Anonymous Monk

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