This creates a new plugin system which hooks into a handful of reader
operations in order to allow plugins to add language-specific support
where the default reader falls short. The two hooks added are:
* During hold-without-pan taps, language plugins can modify the
selection in order to better match what users expect koreader to
highlight when selecting a single word.
The vast majority of CJK language words are more than one character,
but KOReader treats all CJK characters as a single word by default,
so adding this hook means that readers no longer need to manually
select the whole word every time they need to look something.
* During dictionary lookup, language plugins can propose alternative
candidate words to look up if the selected word could not be found in
the dictionary.
This is pretty necessary for Japanese and Korean, both of which are
highly agglutinative languages and the fuzzy searching system of
StarDict is simply not usable because often the inflection of the
word is so much longer than the dictionary form that sdcv decides to
chop off the actual word and search for the inflection (which yields
useless results).
This system is of particular interest for readers of CJK languages
(without this, looking up words using KOReader was fairly painful) but
this system is designed to be minimal and language-agnostic enough that
other languages could make use of it by creating their own plugins if
the default "whole word" highlight and fuzzy-search system doesn't match
their needs.
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
