@directory_read(path:string)

The first version of this command returns a MAP (dictionary) where the keys are the names of the file located in the directory specifeid by path. The subdirectory do not appears in the map. The value associated to a key is the key itself.
If level is specified, the listing is extended to the subdirectories up to level of nestings. A sub-directory is described by a key (a string specifying its name) and a map describing its content.
If ["ext1", "ext2", ...] is specified, only the files with theses extensions are listed.