--- a
+++ b/src/common/syngroups.h
@@ -0,0 +1,40 @@
+/* Copyright (C) 2015 J.F.Dockes
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the
+ *   Free Software Foundation, Inc.,
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifndef _SYNGROUPS_H_INCLUDED_
+#define _SYNGROUPS_H_INCLUDED_
+
+#include <string>
+#include <vector>
+
+// Manage synonym groups. This is very different from stemming and
+// case/diac expansion because there is no reference form: all terms
+// in a group are equivalent.
+class SynGroups {
+public:
+    SynGroups(const std::string& fname);
+    ~SynGroups();
+    std::vector<std::string> getgroup(const std::string& term);
+    bool ok();
+private:
+    class Internal;
+    Internal *m;
+    SynGroups(const SynGroups&);
+    SynGroups& operator=(const SynGroups&);
+};
+
+#endif /* _SYNGROUPS_H_INCLUDED_ */