ParseCmd.vim

" Parses Vimscript commands
" Caveats:
" - Assumes that "a:source" is a well-formed single-line Vim command; it doesn't always fail gracefully otherwise
" - Assumes there is only one command (i.e. "|"s are part of the arguments of the command and aren't used as separators)
" - For ":!" commands, "cmd" is an empty string, "has_bang" is TRUE, and "args" is the entire shell command
func ParseCmd(source) abort
	" sorry.
	let res = matchlist(a:source, '^[ \t:]*\%(\(\%([%.$,;]\|[''\\].\|[-+]\?\d\+\%(\s*match\)\@!\|\([/?]\).\{-\}[^//]\%(\\\\\)*\%(\2\|$\)\)*\)\s*\(\%(\a\|\d\)*\)\(!\?\)\s*\(.*\)\&[^"#]\)')
	return empty(res) ? {} : #{
\		source: res[0],
\		range: res[1],
\		cmd: substitute(res[3], '^\(\d\+\)\s*\(.*\)', '\1\2', ''),
\		has_bang: !empty(res[4]),
\		args: res[5],
\	}
endfunc