REWRITE_RULE
Rewrite.REWRITE_RULE : (thm list -> thm -> thm)
Rewrites a theorem including built-in tautologies in the list of rewrites.
Rewriting a theorem using REWRITE_RULE
utilizes as
rewrites two sets of theorems: the tautologies in the ML list
implicit_rewrites
and the ones supplied by the user. The
rule searches top-down and recursively for subterms which match the
left-hand side of any of the possible rewrites, until none of the
transformations are applicable. There is no ordering specified among the
set of rewrites.
Variants of this rule allow changes in the set of equations used:
PURE_REWRITE_RULE
and others in its family do not rewrite
with the theorems in implicit_rewrites
. Rules such as
ASM_REWRITE_RULE
add the assumptions of the object theorem
(or a specified subset of these assumptions) to the set of possible
rewrites.
The top-down recursive search for matches may not be desirable, as
this may increase the number of inferences being made or may result in
divergence. In this case other rewriting tools such as
ONCE_REWRITE_RULE
and GEN_REWRITE_RULE
can be
used, or the set of theorems given may be reduced.
See GEN_REWRITE_RULE
for the general strategy for
simplifying theorems in HOL using equational theorems.
Does not fail, but may diverge if the sequence of rewrites is non-terminating.
Used to manipulate theorems by rewriting them with other theorems.
While resulting in high degree of automation, REWRITE_RULE
can spawn a large number of inference steps. Thus, variants such as
PURE_REWRITE_RULE
, or other rules such as
SUBST
, may be used instead to improve efficiency.
Rewrite.ASM_REWRITE_RULE
,
Rewrite.GEN_REWRITE_RULE
,
Rewrite.ONCE_REWRITE_RULE
,
Rewrite.PURE_REWRITE_RULE
,
Conv.REWR_CONV
, Rewrite.REWRITE_CONV
,
Thm.SUBST