This prevents a warning message, when the function is tried to add
several times. Also while at it, add a '!' so that no error is thrown if
the file is sourced a second times.
Currently the formatter, and not the wordcount plugin, is responsible
for providing the wordcount as well as formatting it. The default
formatter allows visual mode word counting, although this is not
documented.
The new interface - a transform() function, allows the main wordcount
plugin to internalise this logic. Providing the wordcount simplifies
formatter implementations:
- All formatters can display the visual wordcount.
- Formatters do not have to worry about compatibility with different
vim versions.
The old format() function can now be deprecated, although the wordcount
plugin retains compatibility with formatters using it. The default
formatter will also be used as a fallback if no suitable function is
found.
The default formatter is rewritten to use the new interface.
1) allow for custom formatting of the output of the wordcount formatter
This allows for formatting numbers correctly e.g. 1,042 in English
locale and 1.042 in German locale.
2) cache values, so that no on every cursor move the wordcount needs to
be recalculated.
