In vim 7.3, the strdisplaywidth function was added to give an accurate
count of the number of screen columns that will be taken up by a given
string. Tabular was written before vim 7.3, and was implementing this
functionality itself (at least for tabs; it wasn't trying to handle
doublewide characters).
This changeset allows us to take advantage of strdisplaywidth where it
exists.
The original implementation had some serious problems with delimiters
that were allowed to match with zero-width. This should correct
https://github.com/godlygeek/tabular/issues/3 - please let me know if
you find any regressions!
Per tpope:
"I just discovered the second of the two tabular fixes I gave you
doesn't work properly if the delimiter is at the very beginning of the
line... [It] pretended the leading whitespace was part of the padding,
which doesn't help if there's no leading whitespace."
This reverts commit 16f7b1e204.
The logic to clear a:lines and replace it with the return of the
function failed pretty miserably when the function returned a:lines. It
cleared a:lines and then replaced it with the (now empty) elements.
