Needed in Sage is

• a rewrite in Cython, for speed,
• special decoding algorithms, also in Cython,
• for special decoders, it seems to me that one either needs

1. more classes (eg, a CyclicCodes class), each of which will have a decode method, or
2. another attribute, such as a name (string) which can be used to determine which decoder method to use.

• codes over Rings (Cesar Agustin Garcia Vazquez is working on this)
• codes defined from finite groups fings – for example split group codes,
• a fast minimum distance function (followed by a fast weight distribution function), valid for all characteristics.

It seems more “Pythonic” to add more classes for decoders, but I am not sure.