Perl module for subroutine signatures with no source filter

 With signatures, you can specify subroutine signatures and have
 variables automatically defined within the subroutine. Note that,
 although the syntax is very similar, the signatures provided by this
 module are not to be confused with the prototypes described in
 perlsub. All this module does is extracting items of @_ and assigning
 them to the variables in the parameter list. No argument validation
 is done at runtime.