I still do not understand your original reasons for wanting to use prototypes, nor do I know if hippo's reply has dissuaded you, but if you are not dissuaded, here's an example of why prototypes are not useful as you seem to wish to use them:
c:\@Work\Perl\monks>perl -wMstrict -le
"use Data::Dump qw(dd);
;;
sub S_ { my %h = @_; dd \%h; }
sub Sh (%) { my %h = @_; dd \%h; }
sub Sa (@) { my %h = @_; dd \%h; }
;;
S_(qw(a b c));
Sh(qw(a b c));
Sa(qw(a b c));
"
Odd number of elements in hash assignment at -e line 1.
{ a => "b", c => undef }
Odd number of elements in hash assignment at -e line 1.
{ a => "b", c => undef }
Odd number of elements in hash assignment at -e line 1.
{ a => "b", c => undef }
The warning is in the 'misc' class, and escalating such warnings to FATALity would at least prevent the code from soldiering on regardless, but of course that has nothing to do with the prototype.
Give a man a fish: <%-{-{-{-<
|