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      Read-ACL2-oracle

      Pop the oracle field of the state

      ACL2 has a mutable `state' that contains a number of fields; see state. One of these fields is a list, called the acl2-oracle field. There are no constraints on the elements of this list; thus, you will not be able to prove anything about those elements. However, as a convenience, ACL2 permits you to evaluate the form (read-acl2-oracle state), which returns the multiple value (mv nil nil state).

      The ACL2 implementation uses read-acl2-oracle, but you will likely find this function to be useless unless you do advanced, scurrilous things using trust tags (see defttag).

      The following definition is the logical definition of read-acl2-oracle, but as explained above does not really characterize its behavior under the hood.

      Function: read-acl2-oracle

      (defun read-acl2-oracle (state-state)
        (declare (xargs :guard (state-p1 state-state)))
        (mv (null (acl2-oracle state-state))
            (car (acl2-oracle state-state))
            (update-acl2-oracle (cdr (acl2-oracle state-state))
                                state-state)))