this sounds very fun! For a zillion of XPD I'd write for you something better :)

No, seriously: parsing perl with regexes? "Only perl can parse Perl" see also On Parsing Perl

Above statements and link comes from PPI documentation.. and yes PPI works!

You can give a try to one of most underestimated CUFP of mines: Repeatedly edit a file hacking PPI::Cache and use it to parse PPI::Statement::Sub class in a perl document. Let see it at work:

perl ppi-editor.pl

cache file last_hex_id_file.sto not found.           # it search for p
+revious runs in the hardcoded filename last_hex_id_file.sto
Insert the full path of a new file to edit and press enter (or CTRL-C 
+to terminate)
FILE PATH:./Exp.pm                                   # <---- loading a
+ file
loading from cache ok
'last_hex_id_file.sto' succesfully read: using 5a459de7e28b9b423d7c8d5
+ba988fbdb
Which PPI class do you want to edit?
PPI CLASS:PPI::Statement::Sub                        # <---- selecting
+ a PPI class to work on


Each element of the type PPI::Statement::Sub will be proposed for edit
+ (the content).
insert your new input terminating it with CTRL-Z on a empty line.
use a bare ENTER to skip the current element

STATEMENT: sub new{
        my $class = shift;
        my $validated = _validate( $_[0] );
        return bless {
                validated => $validated,
                stored    => [],
        },$class;
}
CONTENT: sub new{
        my $class = shift;
        my $validated = _validate( $_[0] );
        return bless {
                validated => $validated,
                stored    => [],
        },$class;
}

EDIT:

....                                    # <---- and so on for every su
+b statement


storing cache hex_id: 5a459de7e28b9b423d7c8d5ba988fbdb in last_hex_id_
+file.sto
Enter a filename if you want to save the current version (or ENTER to 
+skip)
OUTPUT FILE:
[download]

You can use the above code as skeleton to automatically inspect every sub and then inspect each shift or assignement coming from @_ to change the sub adding signatures. Should be fun!

I suggest you a final diff log just to review what happened to your code: "unexpected is always a possiblity" :)

L*

UPDATE See PPI::Element to see the difference between statement and content ..in effect i forgot it :) but relaunching my program to inspect PPI::Token::Quote class will demonstrate the difference well enough:

perl ppi-editor.pl

'last_hex_id_file.sto' succesfully read: using 5a459de7e28b9b423d7c8d5
+ba988fbdb   # it wants to reload previous edited file
Which PPI class do you want to edit?                                  
+            # if it finds last_hex_id_file.sto
PPI CLASS:PPI::Token::Quote                                           
+            # <-- search for Quote


Each element of the type PPI::Token::Quote will be proposed for edit (
+the content).
insert your new input terminating it with CTRL-Z on a empty line.
use a bare ENTER to skip the current element

STATEMENT: croak "No arg!" unless $_[0];                              
+            # statement including the PPI::Element
CONTENT: "No arg!"                                                    
+            # content of the PPI::Element itself

EDIT:"No arguments!"                                                  
+            # a minimal change
EDIT:^Z
storing cache hex_id: 057d482fed857c338ec5ff25f2312900 in last_hex_id_
+file.sto
Enter a filename if you want to save the current version (or ENTER to 
+skip)
OUTPUT FILE:./Exp-bis.pm                                              
+            # save to a new file to play nicely..

C>diff Exp.pm Exp-bis.pm                                              
+            # check it out!

17c17
<       croak "No arg!" unless $_[0];
---
>       croak "No arguments!" unless $_[0];
[download]