I'm building a data structure from a config file that looks roughly like this (doing a single pass populating hash entries as they are encountered, not looking ahead): 
# Define a page
page <page key>
{
   toolbar standard;
};
# Define a standard toolbar
toolbar standard
{
   item
   {
      <item config>
   };
};

[download]

When I encounter toolbar standard; in the page config I want to create a blank hash key that will get filled later with the actual definition of toolbar standard. I've tried the following: 

# Encounter the toolbar standard; line in the page config

# Doesn't actually do anything
$page->{<page_key>}{'toolbar'} = $toolbar->{'standard'};

# complains about standard getting re-defined
$toolbar->{'standard'} ||= {};  # also tried undef and dummy value ins
+tead of {} with no luck
$page->{<page_key>}{'toolbar'} = $toolbar->{'standard'};

# $toolbar->{'standard'} is actually populated sometime after I proces
+s $page->{<page_key>}

[download]

Is there any way to get the toolbar def in the page config point to a bucket that will be filled when the toolbar section is processed?

In reply to Defining a hash key for later use by amw1

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