+"""WSGI handler for serving chained WSGI modules from physical files
+
+The WSGI handler in this module examines the SCRIPT_FILENAME variable
+of the requests it handles -- that is, the physical file corresponding
+to the request, as determined by the webserver -- determining what to
+do with the request based on the extension of that file.
+
+By default, it handles files named `.wsgi' by compiling them into
+Python modules and using them, in turn, as chained WSGI handlers, but
+handlers for other extensions can be installed as well.
+
+When handling `.wsgi' files, the compiled modules are cached and
+reused until the file is modified, in which case the previous module
+is discarded and the new file contents are loaded into a new module in
+its place. When chaining such modules, an object named `wmain' is
+first looked for and called with no arguments if found. The object it
+returns is then used as the WSGI application object for that module,
+which is reused until the module is reloaded. If `wmain' is not found,
+an object named `application' is looked for instead. If found, it is
+used directly as the WSGI application object.
+
+This module itself contains both an `application' and a `wmain'
+object. If this module is used by ashd-wsgi(1) or scgi-wsgi(1) so that
+its wmain function is called, arguments can be specified to it to
+install handlers for other file extensions. Such arguments take the
+form `.EXT=MODULE.HANDLER', where EXT is the file extension to be
+handled, and the MODULE.HANDLER string is treated by splitting it
+along its last constituent dot. The part left of the dot is the name
+of a module which is imported, and the part right of the dot is the
+name of an object in that module, which should be a callable of three
+arguments. When files of the given extension are handled, that
+callable is called with the file's absolute path, the WSGI environment
+and the WSGI `start_response' function, in that order. For example,
+the argument `.fpy=my.module.foohandler' can be given to pass requests
+for `.fpy' files to the function `foohandler' in the module
+`my.module' (which must, of course, be importable). When writing such
+handler functions, you will probably want to use the getmod() function
+in this module.
+"""
+