Possible configuration mechanism

[alanz]

At the moment HIE has a list of dependencies in its cabal file, for plugins available to it.
Then in the MainHIE.hs it has a variable of type Plugins which enumerates the plugins to be available.

plugins :: Plugins
plugins = Map.fromList
  [
    -- Note: statically including known plugins. In future this map could be set
    -- up via a config file of some kind.
    ("eg2",  example2Descriptor)
  , ("hare", hareDescriptor)
    -- The base plugin, able to answer questions about the IDE Engine environment.
  , ("base", baseDescriptor)
  ]

A possible future configuration process would be to have a separate exe that can read a HIE config file, containing a list of (plugin name,plugin descriptor,originating package). This exe would then generate a cabal file and Main.hs that calls for the packages to be installed, and sets up the plugins variable.

Hence a local configuration can have whatever plugins are required. This can work since we assume we are doing haskell dev, and have a compiler on hand.

[alanz]

This process could be used for frontend listeners too, to provide aribtrary protocol adapters to the various IDEs

[alanz]

See also #904