Insert directory listing for FILE, formatted according to SWITCHES.
Leaves point after the inserted text.
SWITCHES may be a string of options, or a list of strings.
Optional third arg WILDCARD means treat FILE as shell wildcard.
Optional fourth arg FULL-DIRECTORY-P means file is a directory and
switches do not contain `d', so that a full listing is expected.
This version of the function comes from `ls-lisp.el'.
If the value of `ls-lisp-use-insert-directory-program' is non-nil then
it works exactly like the version from `files.el' and runs a directory
listing program whose name is in the variable
`insert-directory-program'; if also WILDCARD is non-nil then it runs
the shell specified by `shell-file-name'. If the value of
`ls-lisp-use-insert-directory-program' is nil then it runs a Lisp
The Lisp emulation does not run any external programs or shells. It
supports ordinary shell wildcards if `ls-lisp-support-shell-wildcards'
is non-nil; otherwise, it interprets wildcards as regular expressions
to match file names. It does not support all `ls' switches -- those
that work are: A a B C c F G g h i n R r S s t U u X. The l switch is assumed to be always present and cannot be turned off.