redis support

[inukshuk]

Currently, the ML model relies on a feature key-value store that is implemented using kyoto-cabinet or (as a fallback) a regular Ruby hash. Because the feature dictionary is fairly large (probably in excess of 5MB) it is not ideal to use a Ruby hash as this consumes a lot of memory of the Ruby process; the kyoto-cabinet uses a file-based approach which performs very well, however, some users have reported difficulties installing kyoto-cabinet. Redis seems like a good alternative and it should be fairly easy to add as third KV store option.

[dshorthouse]

+1 for Redis

[inukshuk]

Fixed in master. To get it to work you need to adjust Anystyle::Parser::Dictionary.instance.options:

:mode => :redis
:path => unix socket

Or, if you want to use TCP:

:mode => :redis
:host => host
:port => port

The only snag at the moment is that you need to delete the :path option if you want to set a host/port combination, because the redis gem seems to give precedence to path. If we changed path to cabinet then the Kyoto-Cabinet option would not interfere.

[inukshuk]

Alright, switching to redis should be more convenient now. Simply change mode to :redis and set host or path option. The port is set to the default redis port. Further convenience Dictionary#path returns the active path (file, unix socket or host/port, or 'hash' depending on the current mode).

@dshorthouse, let me know if you need anything else. Once we're good to go, we'll release this as 0.1.0.