[Cialug] perl problem

[David Champion]

I'm a total perl n00b, but here's something to consider...

If you add this:

     my $test3 = join("\n", "foo => ${foo}", "bar => ${bar}");

... then print $test3, it displays the local scoped $foo and $bar. I'm 
guessing it has something to do with the way it evaluates the ${$_} 
thingy that's causing your scope issue, even though it looks like your 
$test1 line with the map... in it should evaluate to the same thing as 
my $test3.

Could you stuff the "foo bar" values into an array, then iterate that 
and have it evalute the array contents, instead of using the $_ 
variable? Perl probably has a nice cryptic one-liner for that too.

-dc

Renegade Muskrat 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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