[#] The opinion here is that Lua needs a standard library. Maybe it does, maybe it doesn't, but I want to come to that conclusion myself, that's all.
> APR powers software such as the Apache webserver and Subversion and Lua/APR makes the APR operating system interfaces available to Lua, serving as an extended standard library.
I wrote that description because I like Lua so much that I want to use it not only for embedding but also for writing standalone scripts. However I found that writing standalone Lua scripts that run on both Windows and UNIX is hard because Lua's standard library contains almost no operating system interfaces (e.g. no directory handling and minimal process handling). Also lots of third party libraries either work on Windows or POSIX systems but not both.
After reading your comments and those by compay about Penlight I realized that "standard library" may not be the best way to describe the Lua/APR binding because its focus is really on being an extended operating system interface.