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Perl, sadly, is doing what I tell it to, rather than what I want. I'm using a nested hash as a configuration structure; in the code below is a bare-bones example. Most actions within a page use the same config_item (names changed to protect the innocent), but every now and then an action (e.g. the devious "action3" below) needs a different config_item. So I thought I'd add another nesting level and figure out a way to detect those special cases (they happen often enough, and are useful enough, that I'd hate to factor them out). Other than simplification, the only substantive change from my working code is that my subrefs are named rather than anonymous.

my %runmodes = (
    config_item => 'regular',
    action1 => sub{ print "action = 1" },
    action2 => sub{ print "action = 2" },
    action3 => {
        config_item => 'special',
        subroutine => sub{ print "action = 3" },
    },
);

sub get_config_item {
    my( $runmodes, $action ) = @_;

    my $config_item = $runmodes->{ config_item };

    if( exists $runmodes->{ $action }{ subroutine } ) { # error line
        &{ $runmodes->{ $action }{ subroutine }};
        $config_item = $runmodes->{ $action }{ config_item };
    }
    else {
        &{ $runmodes->{ $action }}
    }

    return $config_item;
}

print ", ", get_config_item( \%runmodes, "action3" ), "\n";
print ", ", get_config_item( \%runmodes, "action1" ), "\n";


# OUTPUT
#
# action = 3, special
# Not a HASH reference at str.pl line 22.
[download]

The "exists" test on the error line isn't the first thing I tried, just the most recent, and it's nicely illustrative of what I want to do. I understand why the error's happening, but I can't think of a way to check for that subref without dying (eval, perhaps, but I'm hoping there's another way). I also know I could standardize the hash structure as follows (with attendent changes in the rest of the code, of course):

my %runmodes = (
    config_item => 'regular',
    action1 => { subroutine => sub{ print "action = 1" }},
    action2 => { subroutine => sub{ print "action = 2" }},
    action3 => {
        config_item => 'special',
        subroutine => sub{ print "action = 3" }},
    },
);
[download]

But two things bug me about that solution. First, those extra "subroutine"s sitting there, redundant, look ugly. Second, regardless of how I solve this particular problem, I still don't know if there's a way to do what I'm trying. Thanks muchly for any assistance.
--
man with no legs, inc.

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