Re: syntax for hashes with variable in name

[jethro]

Your immediate problem is that perl interprets your %{ as a hash slice (see http://docstore.mik.ua/orelly/perl/learn/ch05_05.htm for a small example)

Your larger problem is that you want to use a technique that is a relict from perl4 days and only (if at all) suitable for quick hacks

Instead of using

my %{"platform_$site"};
${"platform_$site"}{"thingy"}= 5;
foreach my $x ( keys %{"platform_$site"}) {
  ...

use multidimensional hashes

my %platform;
$platform{$site}{"thingy"}= 5;
foreach my $x ( keys %{$platform{$site}}) {
  ...

You can use the same technique for your arrays as well, i.e. use a so called HashOfArrays:

push @{$platform{$site}}, 1,2;
$platform{$site}[5]= 5;
foreach my $x ( @{$platform{$site}}) {
  ..

PS: I also notice you don't use 'use warnings;' and 'use strict;' at the beginning of your script. It is highly advisable to include those two lines. Avoids many bug finding sessions later.

[ikegami]

Hash (and array) slices always start with @. No slices start with %.

my %{"$name"};

is the same as

my %{$name}

which is the same as

my %$name;  # Symbolic dereference

which no more works than

my %$ref;   # Generic deference

[ambrus]

Your immediate problem is that perl interprets your %{ as a hash slice

Is this for real?

[Tux]

is it?

Let's rule out the fact that this deals with symbolic references, strict tells us ...

use strict;
use warnings;

{   no strict "refs";
    my $site = "foo";
    my @{"platforms_$site"} = qw( foo bar );
    my %{"platforms_$site"} = map { $_ => 1 } @{"platforms_$site"};
    }

=>

Can't declare array dereference in "my" at xx.pl line 8, near "} ="
Execution of xx.pl aborted due to compilation errors.

The difference is in the assignment part. You cannot use my there. When you drop those, you get:

use strict;
use warnings;

{   no strict "refs";
    my $site = "foo";
    @{"platforms_$site"} = qw( foo bar );
    %{"platforms_$site"} = map { $_ => 1 } @{"platforms_$site"};
    }

Which is still bad coding style, but this works.

[jethro]

It was the best explanation I could find at the moment. But I didn't check with deparse or something.

[equick]

Thanks for your reply.

Yes usually I include strict, but I had just taken an extract of an old script I'm patching to work on that particular function.

I also agree multidimensional arrays are probably the way to go, but if possible I'd rather keep the current variables as they are used throughout the other script.