[Cialug] perl problem

[Jerry Weida]

No, it's not the map call.  It's definitely the quoting within the  
braces around the variable name that seems to be causing this  
behavior.  I'll research it a bit more in my Perl books (maybe even  
check out perlmonks.org) and see if I can find an explaination  
besides my "it's that way because it was designed that way" one.

The following code will produce the same problems:

#!/usr/bin/perl
use strict;
use warnings;

our $foo = "global foo";

{
   my $foo = "local foo";

   print '${foo} = ' . ${foo} . "\n";      # Produces "local foo"
   print '$("foo"} = ' . ${"foo"} . "\n"; # Produces "global foo"
}

On Feb 8, 2006, at 9:51 PM, Tim Wilson wrote:

> My guess is because of the map call using a block.  Since you have  
> another block, you're referencing the global vars instead of the  
> local vars, because the local vars were in a different block.  Just  
> a guess.
>
> On 2/8/06, Renegade Muskrat <dramaley at spatulacity.cx> wrote:
> I have a question regarding Perl. I am having trouble figuring out the
> variable scoping in a script. I've reduced the problem to as simple of
> a code snippet as i can in order to demonstrate it. In the script  
> below
>
> i believe $test1 and $test2 should be the same. But they are not. Any
> ideas why not? And how to make both of them display the local
> variables? Or a better place to ask Perl questions?
>
>
> The script:
>
>
> #!/usr/bin/perl
> use strict;
> use warnings;
>
> our $foo = "global foo";
>
> {
>      my $foo = "local foo";
>      my $bar = "local bar";
>
>      no strict 'refs';
>      my $test1 = join("\n", map { "$_ => ${$_}"; } qw(foo bar));
>      my $test2 = join("\n", "foo => $foo", "bar => $bar");
>
>      print "$test1\n----------\n$test2\n";
> }
>
>
> The output:
>
>
> Use of uninitialized value in concatenation (.) or string at
> ./scratch line 12.
> foo => global foo
> bar =>
> ----------
> foo => local foo
> bar => local bar
>
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>
>
> -- 
> Tim
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