diff --git a/language/types/float.xml b/language/types/float.xml
index d729a43d79..aa46e0ff5e 100644
--- a/language/types/float.xml
+++ b/language/types/float.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<!-- $Revision: 1.4 $ -->
+<!-- $Revision: 1.5 $ -->
 <sect1 xml:id="language.types.float">
  <title>Floating point numbers</title>
 
@@ -29,7 +29,7 @@ $c = 7E-10;
 <![CDATA[
 LNUM          [0-9]+
 DNUM          ([0-9]*[\.]{LNUM}) | ({LNUM}[\.][0-9]*)
-EXPONENT_DNUM (({LNUM} | {DNUM}) [eE][+-]? {LNUM})
+EXPONENT_DNUM [+-]?(({LNUM} | {DNUM}) [eE][+-]? {LNUM})
 ]]>
   </programlisting>
  </informalexample>