EVAL_RULE

bossLib.EVAL_RULE : thm -> thm

Evaluate conclusion of a theorem.

An invocation EVAL_RULE th symbolically evaluates the conclusion of th by applying the defining equations of constants which occur in the conclusion of th. These equations are held in a mutable datastructure that is automatically added to by Hol_datatype, Define, and tprove. The underlying algorithm is call-by-value with a few differences, see the entry for CBV_CONV for details.

Failure

Never fails, but may diverge.

Example

- val th = ASSUME(Term `x = MAP FACT (REVERSE [1;2;3;4;5;6;7;8;9;10])`);
> val th =  [.] |- x = MAP FACT (REVERSE [1; 2; 3; 4; 5; 6; 7; 8; 9; 10])

- EVAL_RULE th;
> val it =  [.] |- x = [3628800; 362880; 40320; 5040; 720; 120; 24; 6; 2; 1]

- hyp it;
> val it = [`x = MAP FACT (REVERSE [1; 2; 3; 4; 5; 6; 7; 8; 9; 10])`]

Comments

In order for recursive functions over numbers to be applied by EVAL_RULE, pattern matching over SUC and 0 needs to be replaced by destructors. For example, the equations for FACT would have to be rephrased as FACT n = if n = 0 then 1 else n * FACT (n-1).

See also

bossLib.EVAL, bossLib.EVAL_TAC, computeLib.CBV_CONV