About

This project contains two Haskell packages that provide Prelude modules for projects that heavily use Polysemy. It is related to the repository incipit, which contains another Prelude that reexports some additional libraries and is separate from this project due to Cabal dependency cycles. The purpose of each package is:

• incipit-base: Exports from base, plus some additional utilities
• incipit-core: Exports from Polysemy proper
• incipit: Additional exports from polysemy-log, polysemy-time, polysemy-conc, polysemy-resume

Usage

Using a custom Prelude requires the use of Cabal mixins to hide the module from base and replace it with IncipitCore or IncipitBase:

For hpack:

dependencies:
  - name: base
    version: '>= 4 && < 5'
    mixin:
      - hiding (Prelude)
  - name: incipit-core
    version: '>= 0.3'
    mixin:
      - (IncipitCore as Prelude)
      - hiding (IncipitCore)

For cabal:

build-depends:
    base >=4 && <5, incipit-core >= 0.3
mixins:
    base hiding (Prelude), incipit-core (IncipitCore as Prelude), incipit-core hiding (IncipitCore)

These packages used to export Prelude, but stack can't deal with that.

Custom Prelude

In order to extend incipit-core (or incipit-base) with a local Prelude, the modules IncipitCore or IncipitBase have to be reexported:

dependencies:
  - name: base
    version: '>= 4 && < 5'
    mixin:
      - hiding (Prelude)
  - incipit-core >= 0.3

module Prelude (
  module Prelude,
  module IncipitCore,
) where

import IncipitCore

projectName :: Text
projectName =
  "spaceship"