nl_tokens: mixin ( a ... sources )
pl_tokens: function mixin ( a ) { var k , key , o ; var len = arguments . length ; for ( k = 1 ; k < len ; k += 1 ) { o = arguments [ k ] ; for ( key in o ) { var v = o [ <mask> ] ; if ( o . hasOwnProperty ( key ) ) { if ( v === undefined || v === null ) { delete a [ key ] ; } else { a [ key ] = o [ key ] ; } } } } return a ; }