multi-mode editing, including literate Haskell and noweb

[Dave Love]

This is an approach to the Emacs todo item concerning multiple major
modes for different parts of a buffer, which hasn't been implemented
as far as I know.  [Although TODO says `a buffer', the item was
written with indirect buffers in mind.]

This isn't well-polished, and probably needs more support from base
Emacs.  It also works better in the development version of Emacs than
in 21.2/3 -- see the commentary.

Below is the basic support, followed by two modes for literate
programming systems.  One is for the noweb tool and the other is for
Haskell's LaTeX `literate'/`inverse comment' convention.  The latter
depends on a simple Haskell mode (also below); some of the components
of the canonical one (from haskell.org) need modifying to work
properly with this approach.

multi-mode.el
Description: basic multi-mode support

noweb.el
Description: noweb mode

haskell-latex.el
Description: literate Haskell mode (LaTeX conventions)

haskell.el
Description: simple Haskell mode