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File-types

Directory-p

Does a path, after following symlinks, refer to a directory?

Signature
(directory-p path &key (state 'state)) → (mv err ans new-state)
Arguments: path — Guard (stringp path).
Returns: err — NIL on success, or an error msg on failure.; ans — Meaningful only when there is no error.
Type (booleanp ans).; new-state — Type (state-p1 new-state), given (force (state-p1 state)).

Definitions and Theorems

Function: directory-p-fn

(defun directory-p-fn (path state)
  (declare (xargs :stobjs (state)))
  (declare (xargs :guard (stringp path)))
  (let ((__function__ 'directory-p))
    (declare (ignorable __function__))
    (b* (((mv err ans state) (file-kind path))
         ((when err) (mv err nil state)))
      (mv err (eq ans :directory) state))))

Theorem: booleanp-of-directory-p.ans

(defthm booleanp-of-directory-p.ans
  (b* (((mv ?err ?ans ?new-state)
        (directory-p-fn path state)))
    (booleanp ans))
  :rule-classes :type-prescription)

Theorem: state-p1-of-directory-p.new-state

(defthm state-p1-of-directory-p.new-state
  (implies (force (state-p1 state))
           (b* (((mv ?err ?ans ?new-state)
                 (directory-p-fn path state)))
             (state-p1 new-state)))
  :rule-classes :rewrite)

Theorem: w-state-of-directory-p

(defthm w-state-of-directory-p
  (b* (((mv ?err ?ans ?new-state)
        (directory-p-fn path state)))
    (equal (w new-state) (w state))))