BRR-COMMANDS.html -- ACL2 Version 6.3

## BRR-COMMANDS

Break-Rewrite Commands

    Major Section:  BREAK-REWRITE

    :a!             abort to ACL2 top-level
    :p!             pop one level (exits a top-level break-rewrite loop)
    :target         term being rewritten
    :unify-subst    substitution making :lhs equal :target
    :hyps           hypotheses of the rule
    :hyp i          ith hypothesis of the rule
    :lhs            left-hand side of rule's conclusion
    :rhs            right-hand side of rule's conclusion
    :type-alist     type assumptions governing :target
    :initial-ttree  ttree before :eval (see ttree)
    :ancestors      negations of backchaining hypotheses being pursued
    :wonp           indicates if application succeed (after :eval)
    :rewritten-rhs  rewritten :rhs (after :eval)
    :final-ttree    ttree after :eval (see ttree)
    :failure-reason reason rule failed (after :eval)
    :path           rewrite's path from top clause to :target
    :frame i        ith frame in :path
    :top            top-most frame in :path
    :ok             exit break
    :go             exit break, printing result
    :eval           try rule and re-enter break afterwards
    :ok!            :ok but no recursive breaks
    :go!            :go but no recursive breaks
    :eval!          :eval but no recursive breaks
    :ok$ runes      :ok with runes monitored during recursion
    :go$ runes      :go with runes monitored during recursion
    :eval$ runes    :eval with runes monitored during recursion
    :help           this message
    :standard-help  :help message from ACL2 top-level

Break-rewrite is just a call of the standard ACL2 read-eval-print loop, `ld`, on a ``wormhole'' state. Thus, you may execute most commands you might normally execute at the top-level of ACL2. However, all state changes you cause from within break-rewrite are lost when you exit or `:eval` the rule. You cannot modify stobjs from within the break. See break-rewrite for more details and see ld for general information about the standard ACL2 read-eval-print loop.