Added initial support for recursive expressions.

Updated docs and tests accordingly.

[SVN r54994]

doc/html/boost_regex/format/boost_format_syntax.html

@@ -32,7 +32,7 @@
         '$', '\', '(', ')', '?', and ':'.
       </p>
 <a name="boost_regex.format.boost_format_syntax.grouping"></a><h5>
-<a name="id667534"></a>
+<a name="id710308"></a>
         <a class="link" href="boost_format_syntax.html#boost_regex.format.boost_format_syntax.grouping">Grouping</a>
       </h5>
 <p>
@@ -40,7 +40,7 @@
         you want a to output literal parenthesis.
       </p>
 <a name="boost_regex.format.boost_format_syntax.conditionals"></a><h5>
-<a name="id667551"></a>
+<a name="id710325"></a>
         <a class="link" href="boost_format_syntax.html#boost_regex.format.boost_format_syntax.conditionals">Conditionals</a>
       </h5>
 <p>
@@ -79,7 +79,7 @@
         ?{NAME}true-expression:false-expression
       </p>
 <a name="boost_regex.format.boost_format_syntax.placeholder_sequences"></a><h5>
-<a name="id667604"></a>
+<a name="id710377"></a>
         <a class="link" href="boost_format_syntax.html#boost_regex.format.boost_format_syntax.placeholder_sequences">Placeholder
         Sequences</a>
       </h5>
@@ -319,7 +319,7 @@
         as a literal.
       </p>
 <a name="boost_regex.format.boost_format_syntax.escape_sequences"></a><h5>
-<a name="id667947"></a>
+<a name="id710721"></a>
         <a class="link" href="boost_format_syntax.html#boost_regex.format.boost_format_syntax.escape_sequences">Escape
         Sequences</a>
       </h5>