reorganize keyword creation for legacy tokenizer

- only save partial words without internal spaces
- consider comma and semicolon a separator of full words
- consider parts before an opening bracket a full word
  (but not the part after the bracket)

Fixes #244.

nominatim/tokenizer/legacy_icu_tokenizer.py

@@ -423,8 +423,7 @@ class LegacyICUNameAnalyzer:
         names = place.get('name')
 
         if names:
-            full_names = set((self.make_standard_word(name) for name in names.values()))
-            full_names.discard('')
+            full_names = self._compute_full_names(names)
 
             token_info.add_names(self.conn, full_names)
 
@@ -461,6 +460,25 @@ class LegacyICUNameAnalyzer:
         return token_info.data
 
 
+    def _compute_full_names(self, names):
+        """ Return the set of all full name word ids to be used with the
+            given dictionary of names.
+        """
+        full_names = set()
+        for name in (n for ns in names.values() for n in re.split('[;,]', ns)):
+            word = self.make_standard_word(name)
+            if word:
+                full_names.add(word)
+
+                brace_split = name.split('(', 2)
+                if len(brace_split) > 1:
+                    word = self.make_standard_word(brace_split[0])
+                    if word:
+                        full_names.add(word)
+
+        return full_names
+
+
     def _add_postcode(self, postcode):
         """ Make sure the normalized postcode is present in the word table.
         """