CONV_RULE : conv -> thm -> thm

Makes an inference rule from a conversion.

If c is a conversion, then CONV_RULE c is an inference rule that applies c to the conclusion of a theorem. That is, if c maps a term `t` to the theorem |- t = t', then the rule CONV_RULE c infers |- t' from the theorem |- t. More precisely, if c `t` returns A' |- t = t', then:
       A |- t
   --------------  CONV_RULE c
    A u A' |- t'
Note that if the conversion c returns a theorem with assumptions, then the resulting inference rule adds these to the assumptions of the theorem it returns.

CONV_RULE c th fails if c fails when applied to the conclusion of th. The function returned by CONV_RULE c will also fail if the ML function c is not, in fact, a conversion (i.e. a function that maps a term t to a theorem |- t = t').

  # CONV_RULE BETA_CONV (ASSUME `(\x. x < 2) 1`);;
  val it : thm = (\x. x < 2) 1 |- 1 < 2