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bin/simple_scan  view on Meta::CPAN

   %%now      "@{[scalar localtime]}"

The first example allows you to pass in a value from the environment
variable C<$LANGUAGE>; the second gets the current date and time as a string (so its 
value would be something like "Tue Feb 14 14:21:56 2006").

Lastly, you can use backticked strings to denote a command to be
executed by the shell; the command's output will be used in place of
the quoted string.

As an example, if we have the script C<languages> which looks like this:

  #!/bin/sh
  echo "perl java python ruby"

and the substitution

  %%language `languages`

then the values finally assigned to C<language> would be 
C<perl java ruby python>.

lib/App/SimpleScan/Substitution.pm  view on Meta::CPAN

  # Clone the dictionary, because we're going to modify it with the
  # fixed values. This effectively prunes the substitution tree at the
  # points where we've already done substitutions.
  my %dictionary = (%{ $self->dictionary() }, $line_obj->fixed);
 
  # Localize the slot that contains the dictionary and replace it
  # with our newly-constructed, possibly-pruned one.
  local($self->{dictionary}) = \%dictionary;

  # Find the most-deeply-nested substitutions; we need to do those first;
  # prune out anything that looks like a variable, but isn't (because
  # there's no value for it in the dictionary).
  my @var_names = grep { defined $self->dictionary->{$_} }
                  $self->_deepest_substitution("$line_obj");

  # We have none.
  return $line_obj unless @var_names;

  # What we want to do is to get every possible combination of the
  # active variables in this line from the dictionary, and substitute
  # all these into the line.