nl_tokens: We record where in the input string an argument comes so we can report errors against those string positions . We publish a change event when - ever the text changes
pl_tokens: function Argument ( emitter , text , start , end , prefix , suffix ) { this . emitter = emitter ; this . setText ( <mask> ) ; this . start = start ; this . end = end ; this . prefix = prefix ; this . suffix = suffix ; }