AppConfig takes care of this. From the docs:

       Configuration files may be arranged in blocks as per the
       style of Win32 "INI" files.

           [file]
           site = kfs
           src  = ~/websrc/docs/$site
           lib  = ~/websrc/lib
           dest = ~/public_html/$site

           [page]
           header = $lib/header
           footer = $lib/footer
[download]

Chris
M-x auto-bs-mode