# HG changeset patch
# User Steve Losh <steve@stevelosh.com>
# Date 1504812354 14400
# Node ID ddd06eaac1cb585f60a3df8de40fe370f6f1fd8c
# Parent  6494ca97e78bf96535f05ea08c5b129854910dce
Clean up iset

diff -r 6494ca97e78b -r ddd06eaac1cb src/istruct.lisp
--- a/src/istruct.lisp	Sun Aug 13 00:09:56 2017 -0400
+++ b/src/istruct.lisp	Thu Sep 07 15:25:54 2017 -0400
@@ -27,7 +27,11 @@
     (finally (return result))))
 
 
-(defgeneric iset (instance slot new-value))
+;; (defgeneric iset (instance slot new-value))
+(defun iset (instance slot new-value)
+  (let ((result (copy-structure instance)))
+    (setf (slot-value result slot) new-value)
+    result))
 
 (defun iset-in (instance slot-path new-value)
   (destructuring-bind (slot . remaining) slot-path
@@ -67,15 +71,6 @@
     `(defstruct ,name
        ,@(mapcar #'build-slot slots)))
 
-  (defun build-iset (name slots)
-    `(defmethod iset ((instance ,name) slot new-value)
-       (,(symb 'make- name)
-        ,@(iterate (for (slot . nil) :in slots)
-                   (collect (ensure-keyword slot))
-                   (collect `(if (eq slot ',slot)
-                               new-value
-                               (slot-value instance ',slot)))))))
-
   (defun build-equal? (name slots)
     `(defmethod equal? ((a ,name) (b ,name))
        (and ,@(iterate (for (slot . nil) :in slots)
@@ -98,7 +93,6 @@
     (let ((slots (mapcar #'ensure-list slots)))
       `(progn
          ,(build-immutable-struct-form name slots)
-         ,(build-iset name slots)
          ,(build-equal? name slots)
          ,(build-constructor name slots)
          ',name))))