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Span

Make-span

Basic constructor macro for span structures.

Syntax

(make-span [:start <start>] 
           [:end <end>])

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

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

Definition

This is an ordinary make- macro introduced by fty::defprod.

Macro: make-span

(defmacro make-span (&rest args)
  (std::make-aggregate 'span
                       args '((:start) (:end))
                       'make-span
                       nil))

Function: span

(defun span (start end)
  (declare (xargs :guard (and (positionp start)
                              (positionp end))))
  (declare (xargs :guard t))
  (let ((__function__ 'span))
    (declare (ignorable __function__))
    (b* ((start (mbe :logic (position-fix start)
                     :exec start))
         (end (mbe :logic (position-fix end)
                   :exec end)))
      (list (cons 'start start)
            (cons 'end end)))))