[Haskell-cafe] hledger: mtl vs transformers

Simon Michael simon at joyful.com
Fri Jan 21 12:56:37 CET 2011

On 1/20/11 10:02 PM, Michael Snoyman wrote:
 > Couldn't you depend on either version of mtl?

I currently depend on "mtl", no version.. am I missing your point ?

On 1/21/11 2:50 AM, Dmitry Astapov wrote:
 >  something pulled in newer "process" in the process, which caused another wave of rebuilds.

hledger! As I said. Due to just the kind of dependency bump you're suggesting. (I've since reverted that higher process 

On 1/21/11 2:44 AM, Dmitry Astapov wrote:
> I have many versions of GHC installed, plus I have a Haskell Platform from .debs as provided by Debian/unstable. That
> version of HP still carries GHC 6.12.1 and mtl 1.*

So I think you're saying: "I know I won't be able to install hledger with my standard platform install, but I'm willing 
to upgrade my whole system to mtl 2 for hledger, because at least I know hledger-chart will install in the end."

And I'm saying: I now think it's a better trade-off for now to leave hledger core installable without this pain, and let 
hledger-chart users - who are less numerous, since gtk is relatively difficult, and hledger-chart is for now quite 
limited - deal with the problem (by installing hledger-chart before hledger, or by using --constraint 'mtl>=2'). And, 
though I know few read them, document it as best we can at http://hledger.org/MANUAL.html#installing and 
http://hledger.org/MANUAL.html#installation-issues .

Also I seem to remember 6.12.1 had at least one specific problem, as you suggest, so supporting it might be out of scope...

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