nl_tokens: \ ] \\ \ ^ \ -
pl_tokens: function preservesInCharClass ( value , index , parent ) { if ( value === '^' ) { // Avoid [\^a] turning into [^a] return index === 0 && ! parent . negative ; } if ( value === '-' ) { // Avoid [a\-z] turning into [a-z] return index !== 0 && index !== parent . expressions . length - 1 ; } return / [\]\\] / . <mask> ( value ) ; }