Major Section: TRACE
A trace evisc-tuple, which is set by this utility, provides a means to restrict printing during tracing. See evisc-tuple for an introduction to evisc-tuples; also see set-evisc-tuple and see set-iprint.
By default the ACL2 trace mechanism, trace$, automatically deals
with stobjs, the logical world, and certain other large structures.
See trace$, in particular the documentation of trace$ option :hide.
However, even with that default behavior you may want to restrict what is
printed according to the print-level and print-length of an evisc-tuple;
see evisc-tuple.
Examples:
; Set trace evisc tuple to a standard value, using current Lisp *print-level*
; and *print-length* variables:
(set-trace-evisc-tuple t state)
; Set trace evisc tuple back to its default:
(set-trace-evisc-tuple nil state)
; Set trace evisc tuple to restrict print-level to 3 and print-length to 4,
; while hiding the logical world and suitably printing stobjs even if trace$
; option ``:hide nil'' is used. (Note: calling trace-evisceration-alist
; directly requires removing this function as `untouchable', which requires a
; trust tag; see remove-untouchable.)
(set-trace-evisc-tuple
(evisc-tuple 3 4 (trace-evisceration-alist state) nil)
state)
General Forms:
(set-trace-evisc-tuple nil state) ; trace evisc-tuple set to standard value
(set-trace-evisc-tuple t state) ; trace evisc-tuple set to hide the logical
; world and deal with stobjs even when
; trace$ option ``:hide nil'' is supplied
(set-trace-evisc-tuple evisc-tuple state)
; tracing set to use indicated evisc-tuple
See trace$ for a discussion of ACL2 tracing. The evisc-tuple used by
that trace utility is the one last installed by set-trace-evisc-tuple
(or by set-evisc-tuple for the trace-evisc-tuple) -- initially to the
default of nil -- unless overriden by trace option :evisc-tuple.
Remark. If you use value t, then ACL2 will ensure that the logical
world and stobjs are kept up-to-date in the trace evisc-tuple.
