use strict;
my $sql = <<'--SQL--';
# this is a comment
$a = "simple string";
$b = "string and comment"; # comment

$c = "string with # thing";

# comment with "string"

$d = "very hard" # dasdas
. "to do";
--SQL--

use HOP::Lexer 'string_lexer';
my $lexer = string_lexer(
    $sql,
    [ STRING    => qr/"[^"]+"/     ],
    [ COMMENT   => qr/#[^\n]*/     ],
    [ SPACE     => qr/\s+/, sub {} ],
);

# (continues like the others...)