commit https://github.com/vim/vim/commit/3848e00e0177abdb31bc600234967863ec487233 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Mar 19 18:42:29 2016 +0100 patch 7.4.1604 Problem: Although emoji characters are ambiguous width, best is to treat them as full width. Solution: Update the Unicode character tables. Add the 'emoji' options. (Yasuhiro Matsumoto)

is<F4>foo
{'silent': 0, 'noremap': 0, 'lhs': 'foo<C-V>', 'mode': ' ', 'nowait': 0, 'expr': 0, 'sid': 0, 'rhs': 'is<F4>foo', 'buffer': 0}
{'silent': 1, 'noremap': 1, 'lhs': 'bar', 'mode': 'v', 'nowait': 0, 'expr': 1, 'sid': 0, 'rhs': 'isbar', 'buffer': 1}
{'silent': 0, 'noremap': 0, 'lhs': 'foo', 'mode': ' ', 'nowait': 1, 'expr': 0, 'sid': 0, 'rhs': 'bar', 'buffer': 1}
xrx
yRy
abcd