a # 1 60 R ' msg hang condition                                         '
a # a,[1]  ' $0 if~condition                                            '
a # a,[1]  ' msg                                                        '
a # a,[1]  ' -1*0.5                                                     '
a # a,[1]  ' $0                                                         '
a # a,[1]  '"hang raises domain error if condition is true.             '
a # a,[1]  '"from ''the apl handbook of techniques'' copyright 1978, ibm. '
Lfx a