[libvoikko] Voikko and upcoming changes to Firefox extensions

[Henri Sivonen]

Mozilla has announced that Firefox 57 will only run Web Extensions
(i.e. Chrome/Opera/Edge-style extensions)
(https://blog.mozilla.org/addons/2017/02/16/the-road-to-firefox-57-compatibility-milestones/).
That is, it will not run XPCOM extensions like Mozvoikko.
Additionally, at present, there exists no way for a Web Extension to
provide a spell checking engine.

I'm interested in finding a solution that would allow Firefox 57 and
beyond to use Voikko for spell checking. I'm not proposing any action
yet. First, I'd like to understand the licensing situation, since
licensing has a direct effect on the potential solution space. I'd
also like to understand the applicability of Voikko beyond Finnish and
the code size, which are relevant for analyzing the cost and benefit
of shipping libvoikko in Firefox itself. (To be clear, this is not a
proposal to do so. At this time, I'd just like to understand potential
solution space.)

Have I understood the following correctly?

 * libvoikko is licensed under MPL 1.1 OR GPLv2 or later OR LGPLv2.1
or later at the recipient's choice?
 * The data files that libvoikko needs to ingest in order to be able
to check Finnish spelling are licensed under GPLv2 or later.
(https://github.com/voikko/corevoikko/blob/master/voikko-fi/README.md#copyright-and-license-information)
 * libvoikko-compatible dictionaries that are on the readiness level
that they could quality-wise be exposed to end-users exist for
Finnish, Greenlandic, North Sami and Kven.
(http://divvun.no/libreofficeoxt.html and
http://divvun.org/proofing/otherapps.html )
 * The licensing situation for the Greenlandic, North Sami and Kven
dictionaries is unclear.
(https://victorio.uit.no/langtech/trunk/langs/kal/LICENCE)
 * There are dictionaries for 48 other language in development, also
under unclear licensing status.
(https://victorio.uit.no/langtech/trunk/langs/)
 * The object code size of libvoikko is about 250 KB give or take 20
KB depending on the instruction set architecture. (Or has the code
size gone down with the recent removal of legacy dictionary formats? I
got this number from Ubuntu 16.04.)

Can the grammar checking feature be omitted at compile time? What's
the object code size for libvoikko omitting features other than spell
checking using non-legacy dictionary format? (I tried to find this out
myself, but I failed to succeed at getting autoconf as provided by
Ubuntu 16.04 to generate an error-free configure script for the tip of
the tree from GitHub.)

-- 
Henri Sivonen
hsivonen at hsivonen.fi
https://hsivonen.fi/