From a2a9eab0efd5f48a2063e1acc2f1e6a3b8ba16fa Mon Sep 17 00:00:00 2001
From: Vladimir Sedach <vsedach@gmail.com>
Date: Fri, 24 Aug 2007 20:01:23 +0000
Subject: [PATCH] Added defsetf and (defun (setf examples to the reference.

---
 docs/reference.lisp    | 40 ++++++++++++++++++++++++++++++++++++++++
 t/reference-tests.lisp | 30 ++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/docs/reference.lisp b/docs/reference.lisp
index 5d6dcba..a1ee294 100644
--- a/docs/reference.lisp
+++ b/docs/reference.lisp
@@ -476,6 +476,7 @@ a-variable  => aVariable
 ;;;# Assignment
 ;;;t \index{assignment}
 ;;;t \index{SETF}
+;;;t \index{DEFSETF}
 ;;;t \index{assignment operator}
 
 ; (SETF {lhs rhs}*)
@@ -504,6 +505,45 @@ a-variable  => aVariable
 
 (setf a (- 1 a))         => a = 1 - a;
 
+;;; New types of setf places can be defined in one of two ways: using
+;;; `DEFSETF' or using `DEFUN' with a setf function name; both are
+;;; analogous to their Common Lisp counterparts.
+
+;;; `DEFSETF' supports both long and short forms, while `DEFUN' of a
+;;; setf place generates a JavaScript function name with the __setf_
+;;; prefix:
+
+(defun (setf color) (new-color el)
+  (setf (slot-value (slot-value el 'style) 'color) new-color))
+  => function __setf_color(newColor, el) {
+       el.style.color = newColor;
+     };
+
+(setf (color some-div) (+ 23 "em"))
+  => var _js2 = someDiv;
+     var _js1 = 23 + 'em';
+     __setf_color(_js1, _js2);
+
+
+;;; Note that temporary variables are generated to preserve evaluation
+;;; order of the arguments as they would be in Lisp.
+
+;;; The following example illustrates how setf places can be used to
+;;; provide a uniform protocol for positioning elements in HTML pages:
+
+(defsetf left (el) (offset)
+  `(setf (slot-value (slot-value ,el 'style) 'left) ,offset)) => null
+
+(setf (left some-div) (+ 123 "px"))
+  => var _js2 = someDiv;
+     var _js1 = 123 + 'px';
+     _js2.style.left = _js1;
+
+(progn (defmacro left (el)
+         `(slot-value ,el 'offset-left))
+       (left some-div))
+  => someDiv.offsetLeft;
+
 ;;;# Single argument statements
 ;;;t \index{single-argument statement}
 ;;;t \index{RETURN}
diff --git a/t/reference-tests.lisp b/t/reference-tests.lisp
index bfe29b8..901de02 100644
--- a/t/reference-tests.lisp
+++ b/t/reference-tests.lisp
@@ -265,6 +265,36 @@ x = a + b + c;")
   (setf a (- 1 a))
   "a = 1 - a;")
 
+(test-ps-js assignment-6
+  (defun (setf color) (new-color el)
+  (setf (slot-value (slot-value el 'style) 'color) new-color))
+  "function __setf_color(newColor, el) {
+  el.style.color = newColor;
+};")
+
+(test-ps-js assignment-7
+  (setf (color some-div) (+ 23 "em"))
+  "var _js2 = someDiv;
+var _js1 = 23 + 'em';
+__setf_color(_js1, _js2);")
+
+(test-ps-js assignment-8
+  (defsetf left (el) (offset)
+  `(setf (slot-value (slot-value ,el 'style) 'left) ,offset))
+  "null")
+
+(test-ps-js assignment-9
+  (setf (left some-div) (+ 123 "px"))
+  "var _js2 = someDiv;
+var _js1 = 123 + 'px';
+_js2.style.left = _js1;")
+
+(test-ps-js assignment-10
+  (progn (defmacro left (el)
+         `(slot-value ,el 'offset-left))
+       (left some-div))
+  "someDiv.offsetLeft;")
+
 (test-ps-js single-argument-statements-1
   (return 1)
   "return 1")
-- 
2.20.1