package lexical;

use v5.22;
use strict;
use warnings;
use Filter::Util::Call ;

=head1 NAME

lexical - Lexical use of exported functions

=head1 VERSION

Version 0.01

=cut

our $VERSION = '0.01';


=head1 SYNOPSIS

Pragma to import subs as lexical_subs into the current scope

    use lexical "Scalar::Util" => qw/looks_like_number/;

    print looks_like_number("a15");


=head1 EXPORT

No classic exports, the namespace isn't polluted

=head1 SUBROUTINES/METHODS

=head2 import

=cut

sub import {
    my ($my_pkg, $module, @imports) = @_;

    eval "use $module";                   # TODO quick & dirty

    my $code = q(use experimental 'lexical_subs','refaliasing';);

    $code .= << "__CODE__" for @imports;   # TODO only subs ATM
my sub $_;
\\&$_ = \\&${module}::$_;
__CODE__

    upject($code);

}


sub upject {
   my $injection  = shift;

   # --- exit if undef
   return unless defined $injection;

   # --- adjust line number to disguise injection
   my ($file,$line) = (caller(2))[1,2];
   $line++;
   $injection .= qq{\n# line $line "$file"\n};

   #warn $injection;
   
   # --- add source filter
   filter_add
     (
      sub {
         my $status =
           filter_read_exact(1);        # read one char into $_
         if ( $status  > 0) {
            $_ = $injection .";".$_;    # prepend code once
            filter_del();               # delete source filter
         }
         $status ;
      }

     );


}

=head1 AUTHOR

Rolf Michael Langsdorf, C<< <lanx at cpan.org> >>

# yadda yadda ...

1; # End of lexical