@@ -180,10 +180,29 @@
   ◊dialogue{
     ◊say["Tavi"]{You also write fiction, or you used to. Do you still?}
     ◊say["Lorde"]{The thing is, when I write now, it comes out as songs.}
   }
 }|
+
+@defproc[(index [heading string?] [elements xexpr?] ...) txexpr?]
+
+Creates an entry in the keyword index under @racket[_heading] that points back to this spot in the
+document. If @racket[_elements] is not empty, the web edition of the document will use it as the
+contents of an understated hyperlink to back to @racket[_heading] in the keyword index.
+
+The example below will create two index entries, one under the heading “compassion” and one under
+the heading “cats”:
+
+@codeblock|{
+  #lang pollen
+
+  “I have a theory which I suspect is rather immoral,” Smiley 
+  went on, more lightly. “Each of us has only a quantum of 
+  ◊index["compassion"]{compassion}. That if we lavish our concern
+  on every stray ◊index["cats"] cat we never get to the centre of 
+  things. What do you think of it?” 
+}|
 
 @defproc[(note [#:date date-str non-empty-string?]
                [#:author author string? ""]
                [#:author-url author-url string? ""]
                [#:disposition disp-str string? ""]) txexpr?]