I take a different approach to this issue of making "printf debugging" easier: I have a binding in my text editor so that when I press Ctrl-K, it will turn the variables on the current line into a printout statement, like so:

  # In Perl, I type:
  %some_hash, $some_scalar, @some_list, some_func()

  # and then hit Ctrl-K to turn it into:

  print STDERR "DBG 950($$): ([\%some_hash, \$some_scalar, \@some_list
+, some_func()]):\n\t", Dumper([\%some_hash, $some_scalar, \@some_list
+, some_func()]);
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The random number after DBG makes it easy to search for that debug line. I have similar bindings for shell, java, C, and other languages, some of which need some hints with the types (e.g., my_name:s becomes my_name(%s)). Here's the binding in my Vim perl.vim syntax file:

nmap <C-K> <ESC>!!print_perl_debug STDERR %<RETURN>:w<CR>
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And here's print_perl_debug:

#!/usr/bin/perl -w

$handle = shift || 'STDERR';
$file   = shift || '/dev/null';

$is_php = system(q(grep -q '^<\?PHP$' ) . $file) == 0;

if ($is_php)
{
    while (<STDIN>)
    {
        chomp;
        s/(^\s*)//;
        $space = $1;
        $rand = int(rand 900) + 100;
        print qq(${space}print 'DBG $rand: $_: ' . "[$_]\\n";\n);
    }
}
else
{
    $do_use = system "grep -q '^[^#]*use Data::Dumper' $file";
    while (<STDIN>)
    {
        chomp;
        s/(^\s*)//;
        $space = $1;
        $use = $do_use ? " use Data::Dumper;" : '';

        s/([@%])/\\$1/g;
        s/\$\\\@/\$\@/g; # fix up $@
        $_ = "[$_]" if /,/;
        $rand = int(rand 900) + 100;
        $printable = $_;
        $printable =~ s/(\$|")/\\$1/g;
        my $last = /\S/ ? qq(($printable):\\n\\t", Dumper($_);$use\n) 
+: qq(\\n";\n);

        print $space, 'print ', ($handle eq 'STDOUT' ? '' : "$handle "
+),
                    qq{"DBG $rand(\$\$): $last};
    }
}
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