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Function

Functionp

Recognizer for function structures.

Signature
(functionp x) → *

Definitions and Theorems

Function: functionp

(defun functionp (x)
  (declare (xargs :guard t))
  (let ((__function__ 'functionp))
    (declare (ignorable __function__))
    (and (true-listp x)
         (eql (len x) 3)
         (b* ((name (std::da-nth 0 x))
              (params (std::da-nth 1 x))
              (body (std::da-nth 2 x)))
           (and (symbol-valuep name)
                (symbol-value-listp params)
                (ttermp body))))))

Theorem: consp-when-functionp

(defthm consp-when-functionp
  (implies (functionp x) (consp x))
  :rule-classes :compound-recognizer)