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Expression-when

Make-expression-when

Basic constructor macro for expression-when structures.

Syntax

(make-expression-when [:test <test>] 
                      [:then <then>] 
                      [:else <else>])

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

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

Definition

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

Macro: make-expression-when

(defmacro make-expression-when (&rest args)
  (std::make-aggregate 'expression-when
                       args '((:test) (:then) (:else))
                       'make-expression-when
                       nil))

Function: expression-when

(defun expression-when (test then else)
  (declare (xargs :guard (and (expressionp test)
                              (expressionp then)
                              (expressionp else))))
  (declare (xargs :guard t))
  (let ((__function__ 'expression-when))
    (declare (ignorable __function__))
    (b* ((test (mbe :logic (expression-fix test)
                    :exec test))
         (then (mbe :logic (expression-fix then)
                    :exec then))
         (else (mbe :logic (expression-fix else)
                    :exec else)))
      (cons :when (list test then else)))))