Cannot use `is`, `isnot` for variable name

[tyru]

let is = 42

vimlparser: unexpected token: is: line 75 col 5

let isnot = 42

vimlparser: unexpected token: isnot: line 75 col 5

[koron]

tokenizer が先に token として認識しちゃってそう。

vim-vimlparser/autoload/vimlparser.vim

Lines 3301 to 3310 in 4139d51

	elseif c ==# 'i' && r.p(1) ==# 's' && !s:isidc(r.p(2))
	if r.p(2) ==# '?'
	call r.seek_cur(3)
	return self.token(s:TOKEN_ISCI, 'is?', pos)
	elseif r.p(2) ==# '#'
	call r.seek_cur(3)
	return self.token(s:TOKEN_ISCS, 'is#', pos)
	else
	call r.seek_cur(2)
	return self.token(s:TOKEN_IS, 'is', pos)