Function: gv-get

gv-get is an autoloaded and byte-compiled function defined in gv.el.gz.

Signature

(gv-get PLACE DO)

Documentation

Build the code that applies DO to PLACE.

PLACE must be a valid generalized variable. DO must be a function; it will be called with 2 arguments: GETTER and SETTER, where GETTER is a (copyable) Elisp expression that returns the value of PLACE, and SETTER is a function which returns the code to set PLACE when called with a (not necessarily copyable) Elisp expression that returns the value to set it to. DO must return an Elisp expression.

Source Code

;; Defined in /usr/src/emacs/lisp/emacs-lisp/gv.el.gz
;;;###autoload
(defun gv-get (place do)
  "Build the code that applies DO to PLACE.
PLACE must be a valid generalized variable.
DO must be a function; it will be called with 2 arguments: GETTER and SETTER,
where GETTER is a (copyable) Elisp expression that returns the value of PLACE,
and SETTER is a function which returns the code to set PLACE when called
with a (not necessarily copyable) Elisp expression that returns the value to
set it to.
DO must return an Elisp expression."
  (cond
   ((symbolp place) (funcall do place (lambda (v) `(setq ,place ,v))))
   ((not (consp place)) (signal 'gv-invalid-place (list place)))
   (t
    (let* ((head (car place))
           (gf (function-get head 'gv-expander 'autoload)))
      (if gf (apply gf do (cdr place))
        (let ((me (macroexpand-1 place
                                 ;; (append macroexpand-all-environment
                                 ;;         gv--macro-environment)
                                 macroexpand-all-environment)))
          (if (and (eq me place) (get head 'compiler-macro))
              ;; Expand compiler macros: this takes care of all the accessors
              ;; defined via cl-defsubst, such as cXXXr and defstruct slots.
              (setq me (apply (get head 'compiler-macro) place (cdr place))))
          (if (and (eq me place) (fboundp head)
                   (symbolp (symbol-function head)))
              ;; Follow aliases.
              (setq me (cons (symbol-function head) (cdr place))))
          (if (eq me place)
              (if (and (symbolp head) (get head 'setf-method))
                  (error "Incompatible place needs recompilation: %S" head)
                (let* ((setter (gv-setter head)))
                  (gv--defsetter head (lambda (&rest args) `(,setter ,@args))
                                 do (cdr place))))
            (gv-get me do))))))))