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better support for multi-valued configuration flags #394

bos opened this Issue · 1 comment

2 participants

Haskell member

(Imported from Trac #401, reported by @dcoutts on 2008-11-08)

For some packages one has to pick one of several mutually exclusive options. For example yi has a number of console or gui front ends.

That can be expressed in terms of boolean flags but it's a little clumsy. We should consider adding some syntactic sugar.

Currently it can be expressed by excluding the choice of picking none:

if flag(gtk)
if flag(vty)
if flag(coca) && os(osx)
if ! ( flag(gtk) || flag(vty) || (flag(coca) && os(osx)) )
buildable: false
That doesn't exclude the possibility of picking two options of course.

In some cases we would want the options to be mutually exclusive and in others we would want to simply force the choice of one option, but multiple options might be possible.

So the question is what kind of syntactic sugar would we like, how would it translate and how would it be exposed to package managers. eg:

flag gui
values: gtk, vty, coca
if flag(gui==gtk)
and it'd translate into boolean choices that forced a choice of one flag being true and the others false.

Needs some thought.

Haskell member

Closing as there's been no activity in years.

We're cleaning up the bug tracker to make it useful again and are thus closing bugs that haven't seen any activity in a long time. Please re-open (or file a new bug) if the problem reappears.

@tibbe tibbe closed this
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