ANNOUNCE: GHC version 6.10.1 - EditLine / terminal incompatibility?

Judah Jacobson judah.jacobson at
Fri Nov 7 12:09:50 EST 2008

On Fri, Nov 7, 2008 at 3:13 AM, Philip K.F. Hölzenspies
<p.k.f.holzenspies at> wrote:
> Dear Ian, all,
> After the announcement, I downloaded and installed the final release of
> 6.10.1. At some prior stage, I used the RC1 release, which had the same bug,
> but I had generally assumed it to be an RC-phenomenon. Which bug? Well...
> It seems editline has some incompatibility with my terminal. Maybe, I should
> configure something differently, but any and all of the control characters I
> type and work for all readline based (and all custom line-readers I have come
> across), but not for the new ghci. Most annoying is the fact that backspace
> doesn't work (instead, the control sequence ^? is printed and pressing enter
> results in "lexical error at character '\DEL'"). However, arrow keys (left
> ^[[D, up ^[[A, right ^[[C and down ^[[B) and common Ctrl+_ combinations (^d,
> ^e, ^a) also give similar errors. It is striking that the lexer does
> recognize them as the correct characters (printed error messages doe say
> \DEL, \EOT, \ENQ, etc).
> I'm using xterm (X.Org on an OpenSuSE 10.3 system and the
> default termcap settings. Any clues? Is this bug known?

If the arrow keys don't work, it's a good sign that ghc just wasn't
built with editline support.  To build againt editline, you will
probably need to install the libedit-devel package.

Hope that helps,

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