--- modules/damieng/schema_documentation/loncapa.html	2017/01/18 18:46:10	1.2
+++ modules/damieng/schema_documentation/loncapa.html	2017/01/30 17:55:42	1.3
@@ -2912,7 +2912,9 @@ ul { margin-top: 0.5em }
   <a name="functionplotcustomrule_0"></a><h3>Element <span class="nomtitre">functionplotcustomrule</span>
 </h3>
     
-      <div class="documentation">        Used to create rules that aren't options using the other rules. The coding is done in Perl and follows Perl syntax. Any variable written inside this rule will be recognized as normal and any evaluation function can be used as well.
+      <div class="documentation">        Used to create rules that aren't options using the other rules. The coding is done inside an answer element, in Perl. Any variable used inside this rule will be recognized normally and any evaluation function can be used as well.
+        The following Perl functions can be used: fpr_val(label), fpr_f(x), fpr_dfdx(x), fpr_d2fdx2(x), fpr_vectorcoords(name), fpr_objectcoords(name), fpr_vectorlength(name), fpr_vectorangle(name).
+        The Perl code should return 1 for a correct answer, 0 for an incorrect one.
       </div>
     
     <div class="indentation">
@@ -2920,7 +2922,7 @@ ul { margin-top: 0.5em }
 <a name="answer_5"></a><h3>Element <span class="nomtitre">answer</span>
 </h3>
           
-            <div class="documentation">              Answer algorithm, normally in Perl
+            <div class="documentation">              Answer algorithm, in Perl
             </div>
           
           Can contain text<br><div class="indentation">