void CompileOperationTokens(List<MmlOperationUse> data, TokenStream stream)
 {
     data.AddRange (new Parser.MmlParser (stream.Source).ParseOperations ());
 }
        MmlSemanticVariable BuildVariableDeclaration(MmlVariableDefinition src)
        {
            var ret = new MmlSemanticVariable (src.Name, src.Type);

            if (src.DefaultValueTokens.Count == 0)
                return ret;

            var stream = new TokenStream (src.DefaultValueTokens, src.Location);
            ret.DefaultValue = new Parser.MmlParser (stream.Source).ParseExpression ();

            return ret;
        }