monitoring : (term -> bool) option ref
STRUCTURE
SYNOPSIS
Monitoring support for evaluation.
DESCRIPTION
The reference variable monitoring provides a simple way to view the operation of EVAL, EVAL_RULE, and EVAL_TAC. The initial value of monitoring is NONE. If one wants to monitor the expansion of a function, defined with constant c, then setting monitoring to SOME (same_const c) will tell the system to print out the expansion of c by the evaluation entrypoints. To monitor the expansions of a collection of functions, defined with c1,...,cn, then monitoring can be set to
   SOME (fn x => same_const c1 x orelse ... orelse same_const cn x)
FAILURE
Never fails.
EXAMPLE
- val [FACT] = decls "FACT";
> val FACT = `FACT` : term

- computeLib.monitoring := SOME (same_const FACT);

- EVAL (Term `FACT 4`);
FACT 4 = (if 4 = 0 then 1 else 4 * FACT (PRE 4))
FACT 3 = (if 3 = 0 then 1 else 3 * FACT (PRE 3))
FACT 2 = (if 2 = 0 then 1 else 2 * FACT (PRE 2))
FACT 1 = (if 1 = 0 then 1 else 1 * FACT (PRE 1))
FACT 0 = (if 0 = 0 then 1 else 0 * FACT (PRE 0))
> val it = |- FACT 4 = 24 : thm
SEEALSO
HOL  Kananaskis-14