\DOC SUBST_MATCH_TAC
\TYPE
{
SUBST_MATCH_TAC :thm_tactic
}
\LIBRARY utils
\SYNOPSIS
Rewrites a goal with an instance of a single theorem, where the instance
may be derived by instantiating variables that occur in the hypothesis of
the given theorem.
\DESCRIBE
The tactic {SUBST_MATCH_TAC thm} strips the theorem {thm} to find an
equation {lhs = rhs} then looks for a match between {lhs} and the
subterms of the goal. Once a match is found the theorem is
instantiated to the particular instance found, and {NEW_SUBST1_TAC}
is used to write the goal with the result.
\FAILURE
The tactic {SUBST_MATCH_TAC thm} will fail if either {thm} does not
strip to and equation, or if no match is found with the left hand side
of the equation.
\EXAMPLE
The tactic
{
SUBST_MATCH_TAC (SYM (UNDISCH SBGP_ID_GP_ID))
}
where
{
SBGP_ID_GP_ID = |- SUBGROUP(G,prod)H ==> (ID(H,prod) = ID(G,prod))
}
when applied to the goal
{
([(--`SUBGROUP((\N. T),$plus)H`--)],(--`H(ID((\N. T),$plus))`--))
}
returns the subgoal
{
([(--`SUBGROUP((\N. T),$plus)H`--)],(--`H(ID(H,$plus))`--))
}
\USES
Rewriting with a theorem that has hypotheses that need to be
instantiated by the matching of the rewriting.
\SEEALSO
{
NEW_SUBST1_TAC, PURE_ONCE_REWRITE_TAC
}
\ENDDOC