From 33e3dac94eaa7cf66be90090d2ff0684950fcd6a Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Thu, 29 Jul 2010 06:56:05 -0500
Subject: [PATCH] add example to scribble/bnf docs

---
 collects/scribblings/scribble/bnf.scrbl | 35 +++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/collects/scribblings/scribble/bnf.scrbl b/collects/scribblings/scribble/bnf.scrbl
index 4650997995..84aa60d8cc 100644
--- a/collects/scribblings/scribble/bnf.scrbl
+++ b/collects/scribblings/scribble/bnf.scrbl
@@ -1,6 +1,7 @@
 #lang scribble/doc
 @(require scribble/manual
           "utils.ss"
+          scribble/bnf
           (for-label scribble/bnf))
 
 @title[#:tag "bnf"]{BNF Grammars}
@@ -8,6 +9,40 @@
 @defmodule[scribble/bnf]{The @racket[scribble/bnf] library
 provides utilities for typesetting grammars.}
 
+For example,
+
+@verbatim[#:indent 2]|{
+@(let ([open @litchar{(}]
+       [close @litchar{)}])
+   @BNF[(list @nonterm{expr}
+              @nonterm{id}
+              @BNF-seq[open @kleeneplus[@nonterm{expr}] close]
+              @BNF-seq[open @litchar{lambda}
+                        open @kleenestar[@nonterm{id}] close
+                        @nonterm{expr} close]
+              @nonterm{val})
+        (list @nonterm{val} 
+              @BNF-alt[@nonterm{number} @nonterm{primop}])
+        (list @nonterm{id}
+              @elem{any name except for @litchar{lambda}})])
+}|
+
+produces the output
+
+@(let ([open @litchar{(}]
+       [close @litchar{)}])
+   @BNF[(list @nonterm{expr}
+              @nonterm{id}
+              @BNF-seq[open @kleeneplus[@nonterm{expr}] close]
+              @BNF-seq[open @litchar{lambda}
+                        open @kleenestar[@nonterm{id}] close
+                        @nonterm{expr} close]
+            @nonterm{val})
+      (list @nonterm{val} 
+            @BNF-alt[@nonterm{number} @nonterm{primop}])
+        (list @nonterm{id}
+              @elem{any name except for @litchar{lambda}})])
+
 See also @racket[racketgrammar].
 
 @defproc[(BNF [prod (cons element? (listof element?))] ...) table?]{