API call for FOR loop to make the main code less cluttered

src/api.ps

@@ -165,6 +165,17 b''
       (this.append-id "qsp-acts"
                 (this.make-act-html title (ps:getprop obj :img))))))
 
+;;; "Syntax"
+
+(defm (root api qspfor) (name index from to step body)
+  (block nil
+    (ps:for ((i from))
+            ((< i to))
+            ((incf i step))
+      (this.set-var name index :num i)
+      (unless (funcall body)
+        (return)))))
+
 ;;; Variable class
 
 (defm (root api *var) (name)

src/ps-macros.lisp

@@ -195,9 +195,10 b''
 ;;; 22for
 
 (ps:defpsmacro qspfor (var from to step &body body)
-  `(block nil
-     (set ,var ,from)
-     (ps:for ()
-             ((< ,var ,to))
-             ((set ,var (+ ,var ,step)))
-             ,@body)))
+  `(api-call qspfor
+             ,(string (second var)) ,(third var) ;; name and index
+             ,from ,to ,step
+             (lambda ()
+               (block nil
+                 ,@body
+                 t))))