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March 2016

35 participants
22 discussions

Question on terminology
by Joel Neely 02 Mar '16

02 Mar '16

IIUC, one would describe fmap as "lifting" a function g into a functor f, in the sense of Functor f => (g a b) -> g a -> g b Is there an inverse concept (? co-lift ?) that describes Functor f => (g a -> g b) -> a -> b Similarly is there standard terminology for "distributing" and "gathering" in the sense of Functor f => f [a] -> [f a] and Functor f => [f a] -> f [a] respectively? References much appreciated! -jn- -- Beauty of style and harmony and grace and good rhythm depend on simplicity. - Plato

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problem installing persistent-postgresql together with persistent-template
by Miro Karpis 02 Mar '16

02 Mar '16

Please,..can you help me with following? I'm trying to install both persistent-postgresql together with persistent-template, but I keep getting: mac:~ miro$ cabal install persistent-template Resolving dependencies... In order, the following would be installed: aeson-0.9.0.1 (latest: 0.11.0.0) (via: persistent-template-2.1.5 persistent-2.2.4 aeson-compat-0.3.1.0) (new version) aeson-compat-0.3.1.0 (via: persistent-template-2.1.5) (new package) persistent-2.2.4 (via: persistent-template-2.1.5) (reinstall) (changes: aeson-0.11.0.0 -> 0.9.0.1) persistent-template-2.1.5 (new package) cabal: The following packages are likely to be broken by the reinstalls: persistent-postgresql-2.2.2 Use --force-reinstalls if you want to install anyway. If I continue with force-reinstall then I broke postgresql. Is there a way to force persistent-template to use 2.2.2 version (I know if I download it and change the dep. in cabal file,....but is that what I should do :) )? running on: mac:~ miro$ cabal --version cabal-install version 1.22.8.0 using version 1.22.7.0 of the Cabal library mac:~ miro$ ghc --version The Glorious Glasgow Haskell Compilation System, version 7.10.3 cheers, m.

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