How do I redefine built in Perl functions?

Question

I want to do two things:

In production code, I want to redefine the open command to enable me to add automagic file logging. I work on data processing applications/f

Answer 1

For open: This worked for me.

use 5.010;
use strict;
use warnings;
use subs 'open';
use Symbol qw;

sub open (*$;@) { 
    say "Opening $_[-1]";
    my ( $symb_arg ) = @_;
    my $symb;
    if ( defined $symb_arg ) { 
        no strict;
        my $caller = caller();
        $symb = \*{$symb_arg};
    }
    else { 
        $_[0] = geniosym;
    }
    given ( scalar @_ ) { 
        when ( 2 ) { return CORE::open( $symb // $_[0], $_[1] ); }
        when ( 3 ) { return CORE::open( $symb // $_[0], $_[1], $_[2] ); }
    }
    return $symb;
}

open PERL4_FH, '<', 'D:\temp\TMP24FB.sql';
open my $lex_fh, '<', 'D:\temp\TMP24FB.sql';

For Printf: Did you check out this question? -> How can I hook into Perl’s print?