At my place of employment, we have a several "command interpreters" that take a files such as

command1 param1=value1 param2=value2
command2 param3=value3 param4=value4
[download]

or even

parallel {
  command1 param1=value1 param2=value2
  command2 param3=value3 param4=value4
}
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there are some other constructs in the "language" but those are the basics. The problem is that I'd like to be able to intersperse Perl amongst the commands such that I can have "scripts" such as

command1 param1=value1 param2=value2
<?perl
if ($last_command_status == FAIL){
?>
  debugging_command debug_param1=debug_value1
<?perl
}
?>
command2 param1=value1 param2=value2
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without changing the format of files that don't have embedded Perl code.

The more complex of the interpreter uses Parse::RecDescent but I'd like to avoid pulling all of the Perl syntax into the interpreter. I've also poked around with Filter::Simple to wrap the non-perl lines by calls to subroutines to handle things but it doesn't "feel" right.

How would you handle this situation?