Fgl-advanced-tracing
List of advanced things you can do while tracing a rewrite rule in FGL
See fgl-trace for instructions to set up tracing of a rule. Here we
discuss various things you can do with such tracing:
- Replace the default printing of trace entry/exit forms with your own:
returning NIL from the on-entry/on-success/on-failure forms prevents printing
of the returned result, and invoking cw or fmt-to-comment-window
within the form lets you customize the printing.
- Abort the application of the rule (cause it to fail) by invoking abort-current-rewrite, even in the :on-success form.
- Trace rule a only while inside certain applications of rule b by
tracing b with the :restore-rules t option and invoking fgl-trace* for rule a within its :on-entry form. (See also fgl-untrace* and fgl-untrace-all*.)
- Invoke trace-repl to enter a read-eval-print loop where you may
interactively examine all the information available in trace forms as well as
doing any of the things discussed here.
- Modify the tracing behavior for the current rule application using fgl-modify-current-tracespec or fgl-delete-current-tracespec,
particularly from the trace-repl.
