		Search-engine friendly clone of the ACL2 documentation.

Std/system/function-queries

Definedp+

Enhanced variant of definedp.

Signature
(definedp+ fn wrld) → yes/no
Arguments: fn — Guard (symbolp fn).; wrld — Guard (plist-worldp wrld).
Returns: yes/no — Type (booleanp yes/no).

This returns the same result as definedp, but it causes an error if called on a symbol that does not name a logic-mode function. The reason for ensuring logic mode is that this utility checks whether the function has an unnormalized body property, but the built-in program-mode functions are defined without having an unnormalized-body property.

Definitions and Theorems

Function: definedp+

(defun
     definedp+ (fn wrld)
     (declare (xargs :guard (and (symbolp fn) (plist-worldp wrld))))
     (let ((__function__ 'definedp+))
          (declare (ignorable __function__))
          (cond ((not (function-symbolp fn wrld))
                 (raise "The symbol ~x0 does not name a function."
                        fn))
                ((not (logicp fn wrld))
                 (raise "The function ~x0 is not in logic mode."
                        fn))
                (t (definedp fn wrld)))))

Theorem: booleanp-of-definedp+

(defthm booleanp-of-definedp+
        (b* ((yes/no (definedp+ fn wrld)))
            (booleanp yes/no))
        :rule-classes :rewrite)

Theorem: function-symbolp-when-definedp+

(defthm function-symbolp-when-definedp+
        (implies (definedp+ fn wrld)
                 (function-symbolp fn wrld)))

Theorem: logicp-when-definedp+

(defthm logicp-when-definedp+
        (implies (definedp+ fn wrld)
                 (logicp fn wrld)))