The problem of type class instances for third-party types is exactly
how I ran into this. Currently I don't know of a good solution, where
"good" means that it meets these criteria:
1. Does not introduce orphan instances
2. Allows for instances to be provided based upon the user's
installed lib
I'm facing this problem too, with hledger. It has optional happstack and
vty interfaces which add to the difficulty and platform-specificity of
installation. Currently I publish all in one package with a cabal flag
for each interface, with happstack off and vty on by default. vty isn't
availabl
Edward,
Thanks for straightening me out; I see the problems better now. In
particular I was missing:
1) Orphaned types (and related design issues) get in the way of
splitting the package.
2) Viral dependencies work in two directions, since "upstream" packages
must pick up your deps to
This has been a lot on my mind lately as my current library provides
additional functionality to data types from a wide array of other packages.
I face a version of Wadler's expression problem.
I provide a set of classes for injecting into monoids/seminearrings/etc. to
allow for quick reductions o
John Lato wrote:
> I think that the proper solution is to break up libraries into
> separate packages as Jeff suggests (buster, buster-ui, etc.), but then
> the total packages on hackage would explode. I don't feel great about
I thought about this a while back and came to the conclusion that the
John Lato wrote:
From: Jeff Heard
Is there a way to do something like autoconf and configure
dependencies at install time? Building buster, I keep adding
dependencies and I'd like to keep that down to a minimum without the
annoyance of littering Hackage with dozens of packages. For instance,
> From: Jeff Heard
>
> Is there a way to do something like autoconf and configure
> dependencies at install time? Building buster, I keep adding
> dependencies and I'd like to keep that down to a minimum without the
> annoyance of littering Hackage with dozens of packages. For instance,
> today
