vi: improvements to undo

The left shift operator ('<') didn't support undo at all; right
shift ('>') required changes to be undone separately for each line.
Allow both types of shift to be undone as a single operation.

Also, neither traditional vi nor vim yank the lines being shifted by
the '<' and '>' commands, so remove that call to yank_delete();

When a repetition count was specified for the '~', 'x', 'X' or 's'
commands the changes had to be undone one character at a time.
Allow undo as a single operation (though the delete and change
parts of the 's' command still have to be undone separately).

function                                             old     new   delta
undo_push_insert                                      37      40      +3
do_cmd                                              4695    4663     -32
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 3/-32)             Total: -29 bytes

v2: Don't break build when FEATURE_VI_UNDO is  disabled.  Don't reset
    'undo_del' too early in '~' handling code.  Code shrink '~'.

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

0 files changed, 0 insertions, 0 deletions