ANNOUNCE: GHC version 6.10.1 - EditLine / terminal incompatibility?

Ian Lynagh igloo at
Mon Nov 10 16:35:20 EST 2008

On Mon, Nov 10, 2008 at 10:39:42AM -0800, Judah Jacobson wrote:
> On Sun, Nov 9, 2008 at 11:03 AM, Don Stewart <dons at> wrote:
> > judah.jacobson:
> >> >
> >> > Note that haskeline has a lot of dependencies and requires
> >> > TemplateHaskell and many other language extensions.
> >>
> >> I'm also somewhat wary of switching to haskeline in ghc-6.10.  I think
> >> these issues could be resolved in time for 6.12, though:
> >
> > haskeline needs /way/ too many extensions for a simple console reader...
> Well, even though the external API of a line reader may look simple,
> under the hood there can be a lot going on

I don't think extensions are an issue for ghci, except for TH (which you
say can be replaced). They doesn't even cause extra problems for
bootstrapping with other Haskell impls, as it's stage >= 2 only.

Extra package dependencies are a pain, but aren't the end of the world.

The big thing, in my opinion, is portability - not in the sense of the
code compiling, but in the sense of "will the arrow keys Just Work if I
run ghci in, say, an rxvt on a Solaris machine"? Although it seems like
editline fails this anyway, even for the common case of xterm/Linux.

Haskell code would also cause fewer build system headaches than linking
to a C library.


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