Feedback.trace

STRUCTURE

SYNOPSIS

Invoke a function with a specified level of tracing.

DESCRIPTION

The trace function is used to set the value of a tracing variable for the duration of one top-level function call.

A call to trace (nm,i) f x attempts to set the tracing variable associated with the string nm to value i. Then it evaluates f x and returns the resulting value after restoring the trace level of nm.

FAILURE

Fails if the name given is not associated with a registered tracing variable. Also fails if the function invocation fails.

EXAMPLE

- load "mesonLib";

- trace ("meson",2) prove
     (concl SKOLEM_THM,mesonLib.MESON_TAC []);

0 inferences so far. Searching with maximum size 0.
0 inferences so far. Searching with maximum size 1.
Internal goal solved with 2 MESON inferences.
0 inferences so far. Searching with maximum size 0.
0 inferences so far. Searching with maximum size 1.
Internal goal solved with 2 MESON inferences.
0 inferences so far. Searching with maximum size 0.
0 inferences so far. Searching with maximum size 1.
Internal goal solved with 2 MESON inferences.
0 inferences so far. Searching with maximum size 0.
0 inferences so far. Searching with maximum size 1.
Internal goal solved with 2 MESON inferences.
  solved with 2 MESON inferences.

> val it = |- !P. (!x. ?y. P x y) = ?f. !x. P x (f x) : thm

- traces();

> val it =
    [{default = 1, name = "meson", trace_level = 1},
     {default = 10, name = "Subgoal number", trace_level = 10},
     {default = 0, name = "Rewrite", trace_level = 0},
     {default = 0, name = "Ho_Rewrite", trace_level = 0}]

SEEALSO

Feedback, register_trace, reset_trace, reset_traces, set_trace, traces, with_flag