zsh completion with virtual path - zsh

Question

I want to create a zsh completion for a tool with a virtual file tree.
e.g. my file tree looks like the following:
/
|- foo/
| |- bar
| |- baz/
| |- qux
|- foobar
My tool mycmd has a subcommand for listing the current directory:
$ mycmd ls
foo/
foobar
$ mycmd ls foo/
bar
baz/
My actual zsh completion looks like this:
_mycmd_ls() {
if [ ! -z "$words[-1]" ]; then
dir=$(dirname /$words[-1])
lastpart=$(basename $words[-1])
items=$(mycmd ls $dir | grep "^$lastpart")
else
items=$(mycmd ls)
fi
_values -s ' ' 'items' ${(uozf)items}
}
_mycmd() {
local -a commands
commands=(
'ls:list items in directory'
)
_arguments -C -s -S -n \
'(- 1 *)'{-v,--version}"[Show program\'s version number and exit]: :->full" \
'(- 1 *)'{-h,--help}'[Show help message and exit]: :->full' \
'1:cmd:->cmds' \
'*:: :->args' \
case "$state" in
(cmds)
_describe -t commands 'commands' commands
;;
(args)
_mycmd_ls
;;
(*)
;;
esac
}
_mycmd
IMHO is _values the wrong utility function. The actual behaviour is:
$ mycmd ls<TAB>
foo/ foobar
$ mycmd ls foo/<TAB> ## <- it inserts automatically a space before <TAB> and so $words[-1] = ""
foo/ foobar
I can't use the utility function _files or _path_files because the file tree is only virtual.

Answer 1

I would suggest to make use of compadd rather _values to get in control of the suffix character appended. Then looking at the available choices, set an empty suffix character in case a virtual directory is part of the result:
_mycmd_ls() {
if [ ! -z "$words[-1]" ]; then
dir=$(dirname /$words[-1])
lastpart=$(basename $words[-1])
items=$(mycmd ls $dir | grep "^$lastpart")
else
items=$(mycmd ls)
fi
local suffix=' ';
# do not append space to word completed if it is a directory (ends with /)
for val in $items; do
if [ "${val: -1:1}" = '/' ]; then
suffix=''
break
fi
done
compadd -S "$suffix" -a items
}