This experimental feature has never been integrated into BNFC.
It is dead code from the point of view of BNFC.
There was some dedicated driver `MultiView.hs` not part of the
compilation process or the testsuite.

This feature, should interest exist, could be maintained in a fork
of BNFC.

Alex 1 has long disappeared, it is not even on hackage.
This backend has not been untested for a long time.
It is just a burden to keep it compilable when refactorings happen.

Alex version 2 does not support unicode and requires GHC <= 7.0 to
build.  It is unlikely that Alex 2 is still used actively.

The --alex2 backend has not been tested for a while.
(BNFC requires now GHC >= 7.10.)

This option has been untested for a long time.
The code produced by this module does not readily compile with GHC.

There is only one Alex backend left: Alex3.

This backend hasn't had a maintainer and has never been covered by the
testsuite.  Alternative language-agnostic tools to generate C# parsers
exist, e.g. https://www.npmjs.com/package/syntax-cli .

This module might have been used in isolation, or it was the start of
a project to add a GF backend.

Tool https://hackage.haskell.org/package/weeder suggested some unused
functions of which I removed some.

Profiles were documented but not tested and did not work out of the
box.  The profile mode was not really core functionality of BNFC, and
design never progressed over the initial stage.  (The syntax
remained ad-hoc: lists/tuples, no nice syntax for the default cases.)

Profiles could be maintained on a fork of BNFC.

Labels can only be identifiers since profiles have been removed.

This backend is released under GPL and the author does not want to
release it under MIT or BSD.

This feature is licensed under GPL can cannot be released under a more
permissive license such as BSD or MIT.

This backend is released under GPL and the author does not want to
release it under MIT or BSD.

This feature is licensed under GPL can cannot be released under a more
permissive license such as BSD or MIT.

…l file

The include paths given to GHCI for running the doctests are more
stable by using dist/build/bnfc-doctests/autogen/ instead of
dist/build/autogen/ which is only present if BNFC is also a library.

This backend is released under GPL and the author does not want to
release it under MIT or BSD.

This feature is licensed under GPL can cannot be released under a more
permissive license such as BSD or MIT.

Integer list(s) (lists) were used in profiles and are now obsolete.