1 SIGNAL
2 labelname
2? VALUE
2.1 expression
2 OFF
2.1 ERROR
2.1 FAILURE
2.1 HALT
2.1 NOVALUE
2.1 SYNTAX
2 ON
2.1 ERROR
2.1 FAILURE
2.1 HALT
2.1 NOVALUE
2.1 SYNTAX
2.2? NAME trapname
3 ;