nl_tokens: there s 3 implementations written in increasing order of efficiency 1 - no Set type is defined
pl_tokens: function uniqNoSet ( arr ) { var ret = [ ] ; for ( var i = 0 ; i < arr . length ; i ++ ) { if ( <mask> . indexOf ( arr [ i ] ) === - 1 ) { ret . push ( arr [ i ] ) ; } } return ret ; }