While it is true that a complete POSIX binding would allow Lua programs to be written for many platforms, it is also true that at least one major platform (Windows) would be left out. It is neither easy nor clean to attempt to graft a POSIX-like API on top of Windows.
Here is brief list and description of known libraries, APIs and systems:
--
Following is a comparison of the ExtensionProposal API with [lposix] and [LuaFileSystem].
-- get environment variable os.getenv posix.getenv -- set/unset environment variable os.setenv posix.putenv posix.setenv posix.unsetenv -- sleep (pause without consuming CPU) os.sleep posix.sleep --[[ os.sleep specifies that the implementation provide sub-second resolution if available. posix.sleep provides only second resolution. --]] -- system information posix.ctermid posix.errno posix.pathconf posix.sysconf posix.ttyname posix.uname
-- get/set current directory os.currentdir posix.getcwd lfs.currentdir os.chdir posix.chdir lfs.chdir -- create/delete directories os.mkdir posix.mkdir lfs.mkdir os.remove posix.rmdir lfs.rmdir --[[ In both "ex" and POSIX systems, os.remove() will remove any directory entry: both files (non-directories) and empty subdirectories. The Lua 5.1 reference says that the standard os.remove() function will remove a directory, but in fact the Microsoft MSVCRT implementation of the C remove() function (on which os.remove() is based) will not remove directories. --]] -- POSIX directory routines posix.link posix.unlink posix.mkfifo posix.readlink posix.symlink
-- list directory os.dir posix.files lfs.dir posix.dir -- get file attributes os.dirent posix.stat lfs.attributes --[[ The "ex" os.dir() iterator returns a table of directory entry attributes including the name, while the posix.files() and lfs.dir() iterators return entry names only. The best comparison of these three functions is via example: --]] require"ex" for e in os.dir() do print(e.name, e.size) end require"lfs" for name in lfs.dir() do if name~="." and name~=".." then print(name, lfs.attributes(name).size) end end require"posix" for name in posix.files() do if name~="." and name~=".." then print(name, posix.stat(name, "size")) end end --[[ os.dir() elides any "." and ".." names while lfs.dir(), posix.dir() and posix.files() include them. posix.dir() is not an iterator; it returns a table with all entry names. --]] -- set file attributes posix.utime lfs.touch posix.chmod posix.chown --[[ The "ex" API says only that the os.dirent() table can be extended with OS-specific attribute values. It would not be unreasonable to add file date information to the standard fields: --]] local age = os.difftime(os.time(), e.modified) e.modified = os.time() -- touch a file -- Check permissions posix.access
-- file locking file:lock lfs.lock file:unlock lfs.unlock -- create anonymous pipe io.pipe
-- spawn process os.spawn posix.fork proc:wait posix.exec posix.wait --[[ os.spawn supports redirection for standard I/O streams (in, out, err) while lposix does not provide full integration with POSIX-style descriptors and therefore does not provide a bind for the POSIX dup() interface. --]] -- signal a process posix.kill -- process information posix.getprocessid posix.getgroup posix.getlogin posix.getpasswd posix.setgid posix.setuid posix.times posix.umask
Note that the "ex" API was based (in part) on LuaFileSystem and its implementations use some code from it.
> py = require "python"
> os = py.import("os")
> =os.listdir('.')
['lua.exe', 'lua51.dll', 'luac.exe']