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Regex-zerolength

Make-regex-zerolength

Basic constructor macro for regex-zerolength structures.

Syntax

(make-regex-zerolength [:pat <pat>] 
                       [:lookback <lookback>] 
                       [:negp <negp>])

This is the usual way to construct regex-zerolength structures. It simply conses together a structure with the specified fields.

This macro generates a new regex-zerolength structure from scratch. See also change-regex-zerolength, which can "change" an existing structure, instead.

Definition

This is an ordinary make- macro introduced by defprod.

Macro: make-regex-zerolength

(defmacro make-regex-zerolength (&rest args)
  (std::make-aggregate 'regex-zerolength
                       args '((:pat) (:lookback . 0) (:negp))
                       'make-regex-zerolength
                       nil))

Function: regex-zerolength

(defun regex-zerolength (pat lookback negp)
  (declare (xargs :guard (and (regex-p pat)
                              (natp lookback)
                              (booleanp negp))))
  (declare (xargs :guard t))
  (let ((__function__ 'regex-zerolength))
    (declare (ignorable __function__))
    (b* ((pat (mbe :logic (regex-fix pat) :exec pat))
         (lookback (mbe :logic (nfix lookback)
                        :exec lookback))
         (negp (mbe :logic (acl2::bool-fix negp)
                    :exec negp)))
      (cons :zerolength (list pat lookback negp)))))