XPath: refactored XPath match, documented localonly and prefixonly api

lib/src/clixon_xpath.c

@@ -60,7 +60,10 @@
  * of the xpath-tree, which is context-dependent. 
  * Best is to send it as a (read-only) parameter to the xp_eval family of functions
  * as an exlicit namespace context.
- * 
+ * 3) localonly flag refers to https://www.w3.org/TR/REC-xml-names/, where :
+ *   PrefixedName   ::=    Prefix ':' LocalPart
+ *  "localonly" means to skip the "Prefix" part, ie namespaces
+ * see nodetest_eval_node() for the semantics of prefix/namespace processing
  */
 #ifdef HAVE_CONFIG_H
 #include "clixon_config.h" /* generated by config & autoconf */
@@ -328,8 +331,8 @@ xpath_tree2cbuf(xpath_tree *xs,
             cprintf(xcb, "%s", clicon_int2str(xpopmap, xs->xs_int));
         break;
     case XP_PATHEXPR:
-        /* [19]    PathExpr ::=  | FilterExpr '/' RelativeLocationPath  
-                                 | FilterExpr '//' RelativeLocationPath 
+        /* [19]    PathExpr ::=  | FilterExpr '/' RelativeLocationPath
+                                 | FilterExpr '//' RelativeLocationPath
         */
         if (xs->xs_s0)
             cprintf(xcb, "%s", xs->xs_s0);
@@ -608,7 +611,7 @@ xpath_parse(const char  *xpath,
  * @param[in]  xcur   XML-tree where to search
  * @param[in]  nsc    External XML namespace context, or NULL
  * @param[in]  xpath  String with XPath 1.0 syntax
- * @param[in]  localonly Skip prefix and namespace tests (non-standard)
+ * @param[in]  localonly Skip prefix and namespace tests
  * @param[out] xrp    Return XPath context
  * @retval     0      OK
  * @retval    -1      Error