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
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;
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. (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-evisc-tuple for the trace-evisc-tuple) -- initially to the
nil -- unless overriden by trace option
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.