[NTG-context] Redefine symbols for new command \morse{.-..}

i'd like to define a new command \define[]\short{\dontleavehmode \blackrule[width=0.4em]\ } \define[]\long {\dontleavehmode \blackrule[width=1.4em]\ } \define[1] \morse {MAGIC} \morse{.-..} should create a \short for every '.' and \long for every '-' But this transcription should be only active in the "morse environment" Is that possible? Who knows the MAGIC? Kind regards, -- Jonas Stein