hub.darcs.net :: simon -> darcsden -> issue

#136use a proper configuration file instead of Settings.hs

maerwald

That would be nice. I might start working on it. Anything important to keep in mind for that? File location?

• maerwaldSat May 9 15:55:30 UTC 2015

  This might be interesting

  https://stackoverflow.com/questions/30140175/moving-from-static-configuration-to-dynamic-configuration/

  http://okmij.org/ftp/Haskell/tr-15-04.pdf

• maerwaldSun May 10 12:16:21 UTC 2015

  Oh, this can be done with the reflection package pretty easily! https://hackage.haskell.org/package/reflection

• maerwaldSun May 10 12:25:36 UTC 2015

  example use

  {-# LANGUAGE Rank2Types, FlexibleContexts, UndecidableInstances #-}
  
  import Data.Reflection
  
  
  data GlobalConfig = MkGlobalConfig {
      getVal1 :: Int
    , getVal2 :: Double
    , getVal3 :: String
  }
  
  
  main :: IO ()
  main = do
    let config = MkGlobalConfig 1 2.0 "test"
    -- initialize the program flow via 'give'
    print $ give config (doSomething "something" 2)
    -- this works too, the type is properly inferred
    print $ give config (3 + 3)
    -- and this as well
    print $ give config (addInt 7 3)
  
  
  -- since we call 'given' inside the function, we need the Given constraint
  doSomething :: (Given GlobalConfig) => String -> Int -> Int
  doSomething str x
    | str == "something"      = x + getVal1 given
    | getVal3 given == "test" = 0 + getVal1 given
    | otherwise               = round (fromIntegral x * getVal2 given)
  
  
  -- no need for Given constraint here
  addInt :: Int -> Int -> Int
  addInt = (+)

• maerwaldSun May 10 19:07:58 UTC 2015

  http://hub.darcs.net/maerwald/darcsden/patch/20150510190023-0bd70

  todo: actually READ user configuration

• maerwaldSun May 10 19:39:16 UTC 2015

  config file parsing and merging with default settings could probably be done with https://hackage.haskell.org/package/ConfigFile-1.1.3/docs/Data-ConfigFile.html

• Simon MichaelFri May 15 19:03:06 UTC 2015

  Deployed and working great, thanks!

  Now I just want a better solution for customizing web content like the site footer, which currently still requires keeping unrecorded Production.hs changes around.

• maerwaldMon May 18 14:09:45 UTC 2015

  Yep, we need to go deeper http://i1.kym-cdn.com/photos/images/original/000/531/557/a88.jpg

  The question is... do we care if the user can access configuration variables within the site-footer etc context? Because that will definitely not be easy.

• Simon MichaelWed May 20 19:21:57 UTC 2015

  It'd be nice to be able to keep the automatic version string and build timestamp there if possible.

• maerwaldSat Nov 28 00:02:07 UTC 2015
  • added tag in-progress