Function: oclosure--lambda

oclosure--lambda is a macro defined in oclosure.el.gz.

Signature

(oclosure--lambda TYPE BINDINGS MUTABLES ARGS &rest BODY)

Documentation

Low level construction of an OClosure object.

TYPE should be a form returning an OClosure type (a symbol). BINDINGS should list all the slots expected by this type, in the proper order. MUTABLE is a list of symbols indicating which of the BINDINGS should be mutable. No checking is performed.

Source Code

;; Defined in /usr/src/emacs/lisp/emacs-lisp/oclosure.el.gz
(defmacro oclosure--lambda (type bindings mutables args &rest body)
  "Low level construction of an OClosure object.
TYPE should be a form returning an OClosure type (a symbol).
BINDINGS should list all the slots expected by this type, in the proper order.
MUTABLE is a list of symbols indicating which of the BINDINGS
should be mutable.
No checking is performed."
  (declare (indent 3) (debug (sexp (&rest (sexp form)) sexp def-body)))
  ;; FIXME: Fundamentally `oclosure-lambda' should be a special form.
  ;; We define it here as a macro which expands to something that
  ;; looks like "normal code" in order to avoid backward compatibility
  ;; issues with third party macros that do "code walks" and would
  ;; likely mishandle such a new special form (e.g. `generator.el').
  ;; But don't be fooled: this macro is tightly bound to `cconv.el'.
  (pcase-let*
      ((`(,prebody . ,body) (macroexp-parse-body body))
       (rovars (mapcar #'car bindings)))
    (dolist (mutable mutables)
      (setq rovars (delq mutable rovars)))
    `(let ,(mapcar (lambda (bind)
                     (if (cdr bind) bind
                       ;; Bind to something that doesn't look
                       ;; like a value to avoid the "Variable
                       ;; ‘foo’ left uninitialized" warning.
                       `(,(car bind) (progn nil))))
                   (reverse bindings))
       ;; FIXME: Make sure the slotbinds whose value is duplicable aren't
       ;; just value/variable-propagated by the optimizer (tho I think our
       ;; optimizer is too naive to be a problem currently).
       (oclosure--fix-type
        ;; This `oclosure--fix-type' + `ignore' call is used by the compiler (in
        ;; `cconv.el') to detect and signal an error in case of
        ;; store-conversion (i.e. if a variable/slot is mutated).
        (ignore ,@rovars)
        (lambda ,args
          (:documentation ,type)
          ,@prebody
          ;; Add dummy code which accesses the field's vars to make sure
          ;; they're captured in the closure.
          (if t nil ,@rovars ,@(mapcar (lambda (m) `(setq ,m ,m)) mutables))
          ,@body)))))