I am attempting to use the Ultisnips Vim plugin to replace a word with its first character, transformed to lowercase (anong other things that aren't relevant to the question). For illustration, I wish to write a snippet
snippet
$1 ${1/ WHAT TO PUT HERE / AND HERE /}
endsnippet
which would output
Word w
One way to do it:
snippet w
$1 ${1/(.).*/\l$1/}
endsnippet
Please note that the replacement strings use Python regexps and syntax, not VimL.
Another way (cleaner, IMO):
snippet w
$1 `!p snip.rv=t[1][0:1].lower()`
endsnippet