my $parser = new Parse::RecDescent( q{
startrule:              
    script
script:
    'script' '[' script_options(s /,/) ']' codeblock
codeblock:
    <perl_codeblock>
script_options:
    script_option '=' qstring
script_option:
    'tag-prefix' |
    'language' |
    'implements-prefix' 
is_printable:           
    /[a-zA-Z0-9_&\#;:\$()\'= ,!\@\/.\[\]\-]+/
qstring:                
    '"' is_printable '"'
}
);