 
     switch (format)
     {
-    case ASCII:
+    case ASCII_FORMAT:
         success = to_ascii( reads_name, output_file, output_index, qencoding, io::SequenceEncoding(encoding_flags) );
         break;
-    case PACKED2:
+    case PACKED2_FORMAT:
         success = to_packed<2u>( reads_name, output_file, output_index, qencoding, io::SequenceEncoding(encoding_flags) );
         break;
-    case PACKED4:
+    case PACKED4_FORMAT:
         success = to_packed<4u>( reads_name, output_file, output_index, qencoding, io::SequenceEncoding(encoding_flags) );
         break;
     }

    const char* idx_name    = NULL;
    bool  forward           = true;
    bool  reverse           = true;
    Format format           = ASCII;
    io::QualityEncoding qencoding = io::Phred33;

    for (int i = 0; i < argc - 2; ++i)


enum Format
{
    ASCII_FORMAT   = 0u,
    PACKED2_FORMAT = 1u,
    PACKED4_FORMAT = 2u,
};

int main(int argc, char* argv[])
