Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!MIDWAY.UCHICAGO.EDU!goer
From: goer@MIDWAY.UCHICAGO.EDU ("Richard L. Goerwitz")
Newsgroups: comp.lang.icon
Subject: test posting of dir lister
Message-ID: <9010210652.AA08963@midway.uchicago.edu>
Date: 21 Oct 90 06:52:24 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: inet
Organization: The Internet
Lines: 143

It's hard to get directory listings from within Icon.  Here are
some routines that do this in a generic way.  The idea of doing
things generically is to avoid OS-specificity, at least on the
level on which these routines are called (not, in other words,
in the actual mechanics of how to get the listing, which are very
OS-specific).

Anyway, I hope someone finds these routines useful.

-Richard

############################################################################
#
#	Name:	 gdl.icn
#
#	Title:	Get directory list 
#
#	Author:	Richard L. Goerwitz
#
#	Version: 1.2
#
############################################################################
#
#  Gdl returns a list containing everything in a directory (whose name
#  must be passed as an argument to gdl).  Nothing fancy.  I use this file
#  as a template, modifying the procedures according to the needs of the
#  program in which they are used.
#
############################################################################
#
#  Requires:  UNIX or MS-DOS
#
############################################################################


procedure gdl(dir)

    getdir := set_getdir_by_os()
    return getdir(dir)

end



procedure set_getdir_by_os()

    # Decide how to get a directory, based on whether we are running
    # under Unix or MS-DOS.

    if find("UNIX", &features)
    then return unix_get_dir
    else if find("MS-DOS", &features)
    then return msdos_get_dir
    else stop("Your operating system is not (yet) supported.")

end



procedure msdos_get_dir(dir)

    # Returns a sorted list of all filenames (full paths included) in
    # directory "dir."  The list is sorted.  Fails on invalid or empty
    # directory.  Aborts if temp file cannot be opened.
    #
    # Temp files can be directed to one or another directory either by
    # manually setting the variable temp_dir below, or by setting the
    # value of the environment variable TEMPDIR to an appropriate
    # directory name.

    local in_dir, filename_list, line
    static temp_dir
    initial {
        temp_dir := 
            (trim(map(getenv("TEMPDIR"), "/", "\\"), '\\') || "\\") |
                ".\\"
    }

    # Get name of tempfile to be used.
    temp_name := get_dos_tempname(temp_dir) |
	stop("No more available tempfile names!")

    # Make sure we have an unambiguous directory name, with backslashes
    # instead of Unix-like forward slashes.
    dir := trim(map(dir, "/", "\\"), '\\') || "\\"

    # Put dir listing into a temp file.
    system("dir "||dir||" > "||temp_name)

    # Put tempfile entries into a list, removing blank- and
    # space-initial lines.  Exclude directories (i.e. return file
    # names only).
    in_dir := open(temp_name,"r") |
	stop("Can't open temp file in directory ",temp_dir,".")
    filename_list := list()
    every filename := ("" ~== !in_dir) do {
        match(" ",filename) | find(" <DIR>", filename) & next
	# Exclude our own tempfiles (may not always be appropriate).
	filename ?:= trim(trim(tab(10)) || "." || tab(13), '. ')
	put(filename_list, map(dir || filename))
    }

    # Clean up.
    close(in_dir) & remove(temp_name)

    # Check to be sure we actually managed to read some files.
    if *filename_list = 0 then fail
    else return sort(filename_list)

end



procedure get_dos_tempname(dir)

    # Don't clobber existing files.  Get a unique temp file name for
    # use as a temporary storage site.

    every temp_name := dir || "icondir." || right(string(1 to 999),3,"0") do {
	temp_file := open(temp_name,"r") | break
        close(temp_file)
    }
    return \temp_name

end



procedure unix_get_dir(dir)

    dir := trim(dir, '/') || "/"
    filename_list := list()
    in_dir := open("/bin/ls -F "||dir, "pr")
    every filename := ("" ~== !in_dir) do {
	match("/",filename,*filename) & next
	put(filename_list, trim(dir || filename, '*'))
    }
    close(in_dir)

    if *filename_list = 0 then fail
    else return filename_list

end