Add note about escaping slashes in regexp

Signed-off-by: martin f. krafft <madduck@madduck.net>
diff --git a/doc/source/operations.rst b/doc/source/operations.rst
index 4801803..a110022 100644
--- a/doc/source/operations.rst
+++ b/doc/source/operations.rst
@@ -103,6 +103,15 @@
   class_mappings:
     - /\.(\S+)$/ tld-\\1
 
+Furthermore, since the outer slashes ('/') are used to "quote" the regular
+expression, *any* slashes within the regular expression must be escaped::
+
+  class_mappings:
+    - /^([^\/]+)\// \\1
+
+This is a bit theoretical right now, as nodenames cannot (yet) include
+slashes, but that might come…
+
 Parameter interpolation
 ------------------------
 Parameters may reference each other, including deep references, e.g.::
diff --git a/reclass/storage/__init__.py b/reclass/storage/__init__.py
index b164d2a..07a0cfe 100644
--- a/reclass/storage/__init__.py
+++ b/reclass/storage/__init__.py
@@ -48,6 +48,7 @@
         regexp = False
         if instr[0] == '/':
             lexer.quotes += '/'
+            lexer.escapedquotes += '/'
             regexp = True
         try:
             key = lexer.get_token()