Proposal: Add --with-libedit flag to the readline package

[Ian Lynagh]

Hi Judah,

On Wed, Jan 09, 2008 at 10:08:20AM -0800, Judah Jacobson wrote:
> 
>  - If it is libedit, we #ifdef out all of the functions not supported
> by libedit. (these are generally low-level APIs not needed by most
> applications, including ghci.) Otherwise, if we're linking against GNU
> readline, we support all the available APIs.
> 
> Thoughts?

I agree with Thorkil's message to the bug report (although I think the
library name should be libedit or editline - I'm a bit confused about
the relationship of the two).

If a Haskell library or program has a build-depends on readline, then it
should get the same functions everywhere; otherwise dependencies are
meaningless. If a program wants to support both libraries then it can do
something like

If flag(readline)
    Build-depends: readline
    CPP-flags: -DUSING_READLINE
Else
    Build-depends: editline
    CPP-flags: -DUSING_EDITLINE

Of course, a third library could do the above conditional dependency and
provide an interface to the intersection of readline and editline's
functionalities. Other programs can then use that third library.


Thanks
Ian