New option -a (append) for hasktags

[Martin Grabmueller]

Hello,

when using the hasktags program as advertised in the users manual, e.g.

  find -name \*.\*hs | xargs hasktags

the tags file(s) get repeatedly truncated when there are so many files
that xargs calls the hasktags program more than once (because otherwise
there would be too many command line arguments).

I have patched hasktags to accept a new command line option

  -a  --append  append to existing CTAGS and/or ETAGS file(s)

which makes hasktags to append to existing tags file(s) instead of
truncating it.  With this patch, it is possible to index the whole
darcs tree for ghc (including all libraries) using the following command:

find -name \*.\*hs | xargs hasktags -a

I will 'darcs send' the resulting patch and hope this patch will be
applied.

Thanks,
  Martin