a # 1 60 R ' msg escape condition                                       '
a # a,[1]  ' $0 if~condition                                            '
a # a,[1]  ' msg                                                        '
a # a,[1]  ' $                                                          '
a # a,[1]  '"escape                                                     '
a # a,[1]  '"from ''the apl handbook of techniques'' copyright 1978, ibm. '
a # a,[1]  '" will leave no trace....better to use Ghang to check       '
a # a,[1]  '" domain errors.                                            '
Lfx a