Fields.hs

{-# LANGUAGE CPP #-}
{-# LANGUAGE MultiWayIf #-}
{-# LANGUAGE OverloadedStrings #-}
{-# OPTIONS_HADDOCK ignore-exports #-}

module Hpack.Fields (cmp) where

import Data.List (elemIndex)
import Data.Maybe (fromMaybe)
import Data.String (IsString ())
#if !MIN_VERSION_base(4,18,0)
import Control.Applicative (liftA2)
#endif
import Data.Foldable (asum)

-- | A default field ordering comparison.
cmp :: (Ord a, IsString a) => a -> a -> Ordering
cmp a b =
  fromMaybe fallback
    . asum
    $ [liftA2 compare (elemIndex a xs) (elemIndex b xs) | xs <- fields]
  where
    -- NOTE: There can be short form conditions with no then or else. In
    -- that case always put condition before the other field name.
    fallback =
      if
          | a == "condition" -> LT
          | b == "condition" -> GT
          | elem a topLevelFields -> LT
          | elem b topLevelFields -> GT
          | otherwise -> a `compare` b

    fields =
      [ topLevelFields
      , libraryFields ++ commonFields
      , runnableFields ++ commonFields
      , flagFields
      , conditionalFields
      , defaultsFields
      ]

-- | All <https://github.com/sol/hpack#top-level-fields top-level> fields combined.
topLevelFields :: IsString a => [a]
topLevelFields =
  headerFields
    ++ repoFields
    ++ packageFields
    ++ commonFields
    ++ stanzasFields

-- | The header subset of
-- <https://github.com/sol/hpack#top-level-fields top-level> fields.
headerFields :: IsString a => [a]
headerFields =
  [ "spec-version"
  , "name"
  , "version"
  , "synopsis"
  , "description"
  , "category"
  , "stability"
  , "homepage"
  , "bug-reports"
  , "author"
  , "maintainer"
  , "copyright"
  , "license"
  , "license-file"
  , "license-files"
  , "tested-with"
  , "build-type"
  ]

-- | The package subset of
-- <https://github.com/sol/hpack#top-level-fields top-level> fields.
packageFields :: IsString a => [a]
packageFields =
  [ "extra-source-files"
  , "extra-doc-files"
  , "data-files"
  , "data-dir"
  ]

-- | The source repository subset of
-- <https://github.com/sol/hpack#top-level-fields top-level> fields.
repoFields :: IsString a => [a]
repoFields =
  [ "github"
  , "git"
  ]

-- | The stanzas subset of
-- <https://github.com/sol/hpack#top-level-fields top-level> fields.
stanzasFields :: IsString a => [a]
stanzasFields =
  [ "custom-setup"
  , "flags"
  , "library"
  , "internal-libraries"
  , "executables"
  , "executable"
  , "tests"
  , "benchmarks"
  , "defaults"
  ]

-- | The <https://github.com/sol/hpack#common-fields common> fields.
commonFields :: IsString a => [a]
commonFields =
  [ "buildable"
  , "source-dirs"
  , "default-extensions"
  , "other-extensions"
  , "ghc-options"
  , "ghc-prof-options"
  , "ghcjs-options"
  , "cpp-options"
  , "cc-options"
  , "c-sources"
  , "cxx-options"
  , "cxx-sources"
  , "js-sources"
  , "extra-lib-dirs"
  , "extra-libraries"
  , "include-dirs"
  , "install-includes"
  , "frameworks"
  , "extra-framework-dirs"
  , "ld-options"
  , "dependencies"
  , "pkg-config-depends"
  , "build-tools"
  , "system-build-tools"
  , "when" -- conditional
  ]

-- | The <https://github.com/sol/hpack#library-fields library> fields.
libraryFields :: IsString a => [a]
libraryFields =
  [ "exposed"
  , "exposed-modules"
  , "generated-exposed-modules"
  , "other-modules"
  , "generated-other-modules"
  , "reexported-modules"
  , "signatures"
  ]

-- | The <https://github.com/sol/hpack#executable-fields executable>,
-- <https://github.com/sol/hpack#test-fields test> and
-- <https://github.com/sol/hpack#benchmark-fields benchmark> fields are all the
-- same.
runnableFields :: IsString a => [a]
runnableFields =
  [ "main"
  , "other-modules"
  , "generated-other-modules"
  ]

-- | The <https://github.com/sol/hpack#flags flag> fields.
flagFields :: IsString a => [a]
flagFields =
  [ "description"
  , "manual"
  , "default"
  ]

-- | The <https://github.com/sol/hpack#-conditionals conditional> fields.
conditionalFields :: IsString a => [a]
conditionalFields =
  [ "condition"
  , "then"
  , "else"
  ]

-- | The <https://github.com/sol/hpack#defaults defaults> fields.
defaultsFields :: IsString a => [a]
defaultsFields =
  [ "github"
  , "ref"
  , "path"
  , "local"
  ]