Feature #891

- Added feature #891, which allows for leftmost partial matches of UUID values.
  Makes direct comparisons for full-length values, and regular expressions for
  partial values.  Note that there is a minimum length of 8 hex digits.
- Added safety parsing mechanism that fails a partial UUID if immediately
  followed by a hex digit.  This allows for numbers longer than 8 digits to not
  be misinterpreted as a UUID.
- Implemented Nibbler::getPartialUUID.
- Implemented unit tests.
@@ -1145,12 +1145,23 @@ const A3 A3::sequence (const A3& input) const

   for (unsigned int i = 0; i < uuids.size (); ++i)
   {
-    if (ids.size ())
+    if (ids.size () + i > 0)
       sequenced.push_back (Arg ("or", Arg::cat_op));

-    sequenced.push_back (Arg ("uuid",        Arg::type_string, Arg::cat_dom));
-    sequenced.push_back (Arg ("=",                             Arg::cat_op));
-    sequenced.push_back (Arg (uuids[i],      Arg::type_string, Arg::cat_literal));
+    // A full-length UUID requires a string comparison.
+    if (uuids[i].length () == 36)
+    {
+      sequenced.push_back (Arg ("uuid",         Arg::type_string, Arg::cat_dom));
+      sequenced.push_back (Arg ("=",                              Arg::cat_op));
+      sequenced.push_back (Arg (uuids[i],       Arg::type_string, Arg::cat_literal));
+    }
+    // A UUID fragment is a leftmost comparison.
+    else
+    {
+      sequenced.push_back (Arg ("uuid",         Arg::type_string, Arg::cat_dom));
+      sequenced.push_back (Arg ("~",                              Arg::cat_op));
+      sequenced.push_back (Arg ("^" + uuids[i], Arg::type_string, Arg::cat_rx));
+    }
   }

   sequenced.push_back (Arg (")", Arg::cat_op));
@@ -1674,11 +1685,11 @@ bool A3::is_uuid (Nibbler& n, std::string& result)
   n.save ();
   result = "";
   std::string uuid;
-  if (n.getUUID (uuid))
+  if (n.getPartialUUID (uuid))
   {
     result += uuid;
     while (n.skip (',') &&
-           n.getUUID (uuid))
+           n.getPartialUUID (uuid))
     {
       result += ',' + uuid;
     }
@@ -1997,13 +2008,13 @@ bool A3::extract_uuid (
   Nibbler n (input);

   std::string uuid;
-  if (n.getUUID (uuid))
+  if (n.getPartialUUID (uuid))
   {
     sequence.push_back (uuid);

     while (n.skip (','))
     {
-      if (!n.getUUID (uuid))
+      if (!n.getPartialUUID (uuid))
         throw std::string (STRING_A3_UUID_AFTER_COMMA);

       sequence.push_back (uuid);

src/Nibbler.h

@@ -75,6 +75,7 @@ public:
   bool getRx (const std::string&, std::string&);
 #endif
   bool getUUID (std::string&);
+  bool getPartialUUID (std::string&);
   bool getDateISO (time_t&);
 #ifdef NIBBLER_FEATURE_DATE
   bool getDate (const std::string&, time_t&);