[Haskell-cafe] Re: [Haskell] ANN: ghci-haskeline 0.1

Andrew Hunter ahunter at cs.hmc.edu
Mon Jan 12 16:41:03 EST 2009

On Mon, Jan 12, 2009 at 12:57:57PM -0800, Judah Jacobson wrote:
> I'm pleased to announce the first release of ghci-haskeline.  This
> package uses the GHC API to reimplement ghci with the Haskeline
> library as a backend.  Haskeline is a library for line input in
> command-line programs, similar to readline or editline, which is
> written in Haskell and thus (hopefully) more easily integrated into
> other Haskell programs.

Perhaps this has already been discussed at length, in which case I
apologize but, well, why provide line input editing at all?

A number of languages/programs (off the top of my head: sml, most
Schemes) don't; the standard method to get line editing is rlwrap.
And this works (in my limited experience) quite well.  The
disadvantage as I see it of using editline or Haskeline or whatever is
that it's going to be sutbly different than other methods; presumably,
people won't like the changes in behavior.

It seems to me that from a UNIX-y separation of concern view, the
right thing to do (as many languages have chosen) is to /not/ provide
line editing, and just let the user do that with any number of
convenient tools that focus on getting/that/ right (like rlwrap.)  Is
there a reason we've not taken that approach?


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