First cross try

Fix CI on FreeBSD
Fix missing import
2020-04-29 20:19:01 +02:00 · 2020-04-29 20:14:38 +02:00 · 2020-04-29 19:36:16 +02:00 · 2020-04-29 19:17:59 +02:00 · 2020-04-29 19:12:58 +02:00 · 2020-04-29 12:38:57 +02:00
34 changed files with 3563 additions and 400 deletions
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -15,12 +15,21 @@ variables:
  variables:
    OS: "LINUX"

-.alpine:
+.alpine:64bit:
  image: "alpine:edge"
  tags:
    - x86_64-linux
  variables:
    OS: "LINUX"
+    BIT: "64"
+
+.alpine:32bit:
+  image: "i386/alpine:edge"
+  tags:
+    - x86_64-linux
+  variables:
+    OS: "LINUX"
+    BIT: "32"

 .darwin:
  tags:
@@ -48,7 +57,7 @@ variables:
  script:
    - ./.gitlab/script/ghcup_version.sh
  variables:
-    JSON_VERSION: "0.0.1"
+    JSON_VERSION: "0.0.2"

 .test_ghcup_version:linux:
  extends:
@@ -133,15 +142,28 @@ test:freebsd:latest:

 ######## linux release ########

-release:linux:
+release:linux:64bit:
  extends:
-    - .alpine
+    - .alpine:64bit
    - .release_ghcup
  before_script:
    - ./.gitlab/before_script/linux/alpine/install_deps.sh
  variables:
    ARTIFACT: "x86_64-linux-ghcup"
    GHC_VERSION: "8.8.3"
+    CABAL_VERSION: "3.2.0.0"
+
+
+release:linux:32bit:
+  extends:
+    - .alpine:32bit
+    - .release_ghcup
+  before_script:
+    - ./.gitlab/before_script/linux/alpine/install_deps.sh
+  variables:
+    ARTIFACT: "i386-linux-ghcup"
+    GHC_VERSION: "8.8.3"
+    CABAL_VERSION: "3.2.0.0"


 ######## darwin release ########
--- a/.gitlab/before_script/freebsd/install_deps.sh
+++ b/.gitlab/before_script/freebsd/install_deps.sh
@@ -15,8 +15,8 @@ mkdir -p "${GHCUP_INSTALL_BASE_PREFIX}"/.ghcup/bin
 # ./ghcup-bin set ${GHC_VERSION}

 # install cabal-3.2.0.0
-curl -sSfL -o freebsd.tar.xz 'https://hasufell.de/f/48aa72dcfaff4c3ea452/?dl=1'
-tar xf freebsd.tar.xz
+curl -sSfL -o cabal-install-3.2.0.0-x86_64-portbld-freebsd.tar.xz 'https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.2.0.0-x86_64-portbld-freebsd.tar.xz&dl=1'
+tar xf cabal-install-3.2.0.0-x86_64-portbld-freebsd.tar.xz
 cp cabal "${GHCUP_INSTALL_BASE_PREFIX}/.ghcup/bin/cabal"
 chmod +x "${GHCUP_INSTALL_BASE_PREFIX}/.ghcup/bin/cabal"

--- a/.gitlab/before_script/linux/alpine/install_deps.sh
+++ b/.gitlab/before_script/linux/alpine/install_deps.sh
@@ -2,6 +2,8 @@

 set -eux

+. "$( cd "$(dirname "$0")" ; pwd -P )/../../../ghcup_env"
+
 apk add --no-cache \
 	curl \
 	gcc \
@@ -12,14 +14,36 @@ apk add --no-cache \
 	make \
 	xz \
 	tar \
-	perl \
-	\
-	cabal \
-	ghc
+	perl
+
+ln -s libncurses.so /usr/lib/libtinfo.so
+ln -s libncursesw.so.6 /usr/lib/libtinfow.so.6
+if [ "${BIT}" = "32" ] ; then
+	curl -sSfL https://downloads.haskell.org/~ghcup/0.1.4/i386-linux-ghcup-0.1.4 > ./ghcup-bin
+else
+	curl -sSfL https://downloads.haskell.org/~ghcup/0.1.4/x86_64-linux-ghcup-0.1.4 > ./ghcup-bin
+fi
+chmod +x ghcup-bin
+./ghcup-bin upgrade
+./ghcup-bin install ${GHC_VERSION}
+# ./ghcup-bin install-cabal ${CABAL_VERSION}
+# install cabal-3.2.0.0
+if [ "${BIT}" = "32" ] ; then
+	curl -sSfL -o cabal-install-3.2.0.0-i386-alpine-linux-musl.tar.xz 'https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.2.0.0-i386-alpine-linux-musl.tar.xz&dl=1'
+	tar xf cabal-install-3.2.0.0-i386-alpine-linux-musl.tar.xz
+	cp cabal-install-3.2.0.0-i386-alpine-linux-musl "${GHCUP_INSTALL_BASE_PREFIX}/.ghcup/bin/cabal"
+else
+	curl -sSfL -o cabal-install-3.2.0.0-x86_64-alpine-linux-musl.tar.xz 'https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.2.0.0-x86_64-alpine-linux-musl.tar.xz&dl=1'
+	tar xf cabal-install-3.2.0.0-x86_64-alpine-linux-musl.tar.xz
+	cp cabal-install-3.2.0.0-x86_64-alpine-linux-musl "${GHCUP_INSTALL_BASE_PREFIX}/.ghcup/bin/cabal"
+fi
+chmod +x "${GHCUP_INSTALL_BASE_PREFIX}/.ghcup/bin/cabal"
+

 # utils
 apk add --no-cache \
-	bash
+	bash \
+	git

 ## Package specific
 apk add --no-cache \
@@ -34,5 +58,4 @@ apk add --no-cache \
 	xz-dev


-. "$( cd "$(dirname "$0")" ; pwd -P )/../../../ghcup_env"

--- a/.gitlab/before_script/linux/install_deps.sh
+++ b/.gitlab/before_script/linux/install_deps.sh
@@ -3,7 +3,7 @@
 set -eux

 sudo apt-get update -y
-sudo apt-get install -y libnuma-dev zlib1g-dev libgmp-dev libgmp10 libssl-dev liblzma-dev
+sudo apt-get install -y libnuma-dev zlib1g-dev libgmp-dev libgmp10 libssl-dev liblzma-dev git wget

 . "$( cd "$(dirname "$0")" ; pwd -P )/../../ghcup_env"

--- a/.gitlab/script/ghcup_release.sh
+++ b/.gitlab/script/ghcup_release.sh
@@ -10,17 +10,21 @@ ecabal() {
 	cabal --store-dir="$(pwd)"/.store "$@"
 }

+git describe
+
 # build
 ecabal update

 if [ "${OS}" = "LINUX" ] ; then
-	ecabal build -w ghc-${GHC_VERSION} -fcurl --ghc-options='-split-sections -optl-static'
+	ecabal build -w ghc-${GHC_VERSION} --ghc-options='-split-sections -optl-static'
+elif [ "${OS}" = "FREEBSD" ] ; then
+	ecabal build -w ghc-${GHC_VERSION} --ghc-options='-split-sections'
 else
-	ecabal build -w ghc-${GHC_VERSION} -fcurl
+	ecabal build -w ghc-${GHC_VERSION}
 fi

 mkdir out
-cp "$(ecabal new-exec --verbose=0 --offline sh -- -c 'command -v ghcup')" .
+cp "$(ecabal new-exec -w ghc-${GHC_VERSION} --verbose=0 --offline sh -- -c 'command -v ghcup')" .
 ver=$(./ghcup --numeric-version)
 cp ghcup out/${ARTIFACT}-${ver}

--- a/.gitlab/script/ghcup_version.sh
+++ b/.gitlab/script/ghcup_version.sh
@@ -14,15 +14,16 @@ eghcup() {
 	ghcup -v -c -s file://$(pwd)/ghcup-${JSON_VERSION}.json "$@"
 }

+git describe

 ### build

 ecabal update

 if [ "${OS}" = "DARWIN" ] ; then
-	ecabal build -w ghc-${GHC_VERSION} -fcurl
-else
 	ecabal build -w ghc-${GHC_VERSION}
+else
+	ecabal build -w ghc-${GHC_VERSION} -finternal-downloader
 fi

 cp "$(ecabal new-exec --enable-tests --verbose=0 --offline sh -- -c 'command -v ghcup')" .
@@ -70,7 +71,11 @@ ghci-$(ghc --numeric-version) --version

 # test installing new ghc doesn't mess with currently set GHC
 # https://gitlab.haskell.org/haskell/ghcup-hs/issues/7
-eghcup install 8.4.4
+if [ "${OS}" = "LINUX" ] ; then
+	eghcup --downloader=wget install 8.4.4
+else # test wget a bit
+	eghcup install 8.4.4
+fi
 [ "$(ghc --numeric-version)" = "${ghc_ver}" ]
 eghcup set 8.4.4
 eghcup set 8.4.4
--- a/HACKING.md
+++ b/HACKING.md
@@ -43,3 +43,22 @@ Kazu Yamamoto [explained it in his PR](https://github.com/yesodweb/wai/pull/752#
 1. Brittany
 2. mtl-style preferred
 3. no overly pointfree style
+
+## Code structure
+
+Main functionality is in `GHCup` module. Utility functions are
+organised tree-ish in `GHCup.Utils` and `GHCup.Utils.*`.
+
+Anything dealing with ghcup specific directories is in
+`GHCup.Utils.Dirs`.
+
+Download information on where to fetch bindists from is in
+`GHCup.Data.GHCupDownloads`.
+
+## Major refactors
+
+1. First major refactor included adding cross support. This added
+   `GHCTargetVersion`, which includes the target in addition to the version.
+   Most of the `Version` parameters to functions had to be replaced with
+   that and ensured the logic is consistent for cross and non-cross
+   installs.
--- a/README.md
+++ b/README.md
@@ -11,6 +11,8 @@ Similar in scope to [rustup](https://github.com/rust-lang-nursery/rustup.rs), [p
   * [Installation](#installation)
   * [Usage](#usage)
     * [Manpages](#manpages)
+     * [Shell-completion](#shell-completion)
+     * [Cross support](#cross-support)
   * [Design goals](#design-goals)
   * [How](#how)
   * [Known users](#known-users)
@@ -68,6 +70,26 @@ handles your haskell packages and can demand that [a specific version](https://c
 For man pages to work you need [man-db](http://man-db.nongnu.org/) as your `man` provider, then issue `man ghc`. Manpages only work for the currently set ghc.
 `MANPATH` may be required to be unset.

+### Shell-completion
+
+Shell completions are in `shell-completions`.
+
+For bash: install `shell-completions/bash`
+as e.g. `/etc/bash_completion.d/ghcup` (depending on distro)
+and make sure your bashrc sources the startup script
+(`/usr/share/bash-completion/bash_completion` on some distros).
+
+### Cross support
+
+ghcup can compile and install a cross GHC for any target. However, this
+requires that the build host has a complete cross toolchain and various
+libraries installed for the target platform.
+
+Consult the GHC documentation on the [prerequisites](https://gitlab.haskell.org/ghc/ghc/-/wikis/building/cross-compiling#tools-to-install).
+For distributions with non-standard locations of cross toolchain and
+libraries, this may need some tweaking of `build.mk` or configure args.
+See `ghcup compile ghc --help` for further information.
+
 ## Design goals

 1. simplicity
--- a/RELEASING.md
+++ b/RELEASING.md
@@ -4,8 +4,11 @@

 2. Add/fix downloads to `GHCupDownloads` module, then run `ghcup-gen gen` to generate the new json and validate it via `ghcup-gen check`.

-3. Commit and git push with tag. Wait for tests to succeed.
+3. Commit and git push with tag. Wait for tests to succeed and release artifacts to build.

-4. Upload the new `ghcup-<ver>.json` to `webhost.haskell.org/ghcup/data/`.
+4. Download release artifacts and upload them `downloads.haskell.org/ghcup`
+
+5. Add release artifacts to GHCupDownloads (see point 2.)
+
+6. Upload the final `ghcup-<ver>.json` to `webhost.haskell.org/ghcup/data/`.

-5. Build ghcup releases for Linux (fully static), mac (with `-fcurl`) and FreeBSD (with `-fcurl`). Upload to `webhost.haskell.org/ghcup/bin/` and update symlinks.
--- a/TODO.md
+++ b/TODO.md
@@ -2,27 +2,39 @@

 ## Now

-* move out GHCup.Version module, bc it's not library-ish
+* try to run exe before upgrade (backup to ~/.ghcup/bin/ghcup.old)
+* allow to build 8.8
+* curl DL does not cache json
+* explain environment variables
+* add --keep=<always|error> option
+
+* allow to switch to curl/wget at runtime
+
+* cross support
+* installing multiple versions of the same
+
+* proper test suite
+* add more logging
+

 ## Maybe

-* maybe: changelog          Show the changelog of a GHC release (online)
+* version ranges in json
 * sign the JSON? (Or check gpg keys?)
 * testing (especially distro detection -> unit tests)

 ## Later

-* i386 support
 * add support for RC/alpha/HEAD versions

 ## Cleanups

-* too many decodeutf8
 * avoid alternative for IO
 * use plucky or oops instead of Excepts

 ## Questions

+* move out GHCup.Version module, bc it's not library-ish?
 * mirror support
 * interactive handling when distro doesn't exist and we know the tarball is incompatible?
 * ghcup-with wrapper to execute a command with a given ghc in PATH?
--- a/app/ghcup-gen/Main.hs
+++ b/app/ghcup-gen/Main.hs
@@ -10,10 +10,10 @@

 module Main where

+import           GHCup.Data.GHCupInfo
 import           GHCup.Types
 import           GHCup.Types.JSON               ( )
 import           GHCup.Utils.Logger
-import           GHCupInfo

 import           Data.Aeson                     ( eitherDecode, encode )
 import           Data.Aeson.Encode.Pretty
--- a/app/ghcup-gen/Validate.hs
+++ b/app/ghcup-gen/Validate.hs
@@ -27,9 +27,12 @@ import           Haskus.Utils.Variant.Excepts
 import           Optics
 import           System.Exit
 import           System.IO
+import           Text.ParserCombinators.ReadP

 import qualified Data.ByteString               as B
 import qualified Data.Map.Strict               as M
+import qualified Data.Text                     as T
+import qualified Data.Version                  as V


 data ValidationError = InternalError String
@@ -61,8 +64,9 @@ validate dls = do
        forM_ (M.toList $ _viArch vi) $ \(arch, pspecs) -> do
          checkHasRequiredPlatforms t v arch (M.keys pspecs)

-    checkGHCisSemver
+    checkGHCVerIsValid
    forM_ (M.toList dls) $ \(t, _) -> checkMandatoryTags t
+    _ <- checkGHCHasBaseVersion

    -- exit
    e <- liftIO $ readIORef ref
@@ -85,7 +89,7 @@ validate dls = do
      [i|FreeBSD missing for #{t} #{v'} #{arch}|]

  checkUniqueTags tool = do
-    let allTags = join $ fmap snd $ availableToolVersions dls tool
+    let allTags = join $ M.elems $ availableToolVersions dls tool
    let nonUnique =
          fmap fst
            .   filter (\(_, b) -> not b)
@@ -105,26 +109,40 @@ validate dls = do
        lift $ $(logError) [i|Tags not unique for #{tool}: #{xs}|]
        addError
   where
-    isUniqueTag Latest      = True
-    isUniqueTag Recommended = True
+    isUniqueTag Latest         = True
+    isUniqueTag Recommended    = True
+    isUniqueTag (Base       _) = False
+    isUniqueTag (UnknownTag _) = False

-  checkGHCisSemver = do
+  checkGHCVerIsValid = do
    let ghcVers = toListOf (ix GHC % to M.keys % folded) dls
-    forM_ ghcVers $ \v -> case semver (prettyVer v) of
-      Left _ -> do
-        lift $ $(logError) [i|GHC version #{v} is not valid semver|]
-        addError
-      Right _ -> pure ()
+    forM_ ghcVers $ \v ->
+      case [ x | (x,"") <- readP_to_S V.parseVersion (T.unpack . prettyVer $ v) ] of
+        [_] -> pure ()
+        _   -> do
+          lift $ $(logError) [i|GHC version #{v} is not valid |]
+          addError

  -- a tool must have at least one of each mandatory tags
  checkMandatoryTags tool = do
-    let allTags = join $ fmap snd $ availableToolVersions dls tool
+    let allTags = join $ M.elems $ availableToolVersions dls tool
    forM_ [Latest, Recommended] $ \t -> case elem t allTags of
      False -> do
        lift $ $(logError) [i|Tag #{t} missing from #{tool}|]
        addError
      True -> pure ()

+  -- all GHC versions must have a base tag
+  checkGHCHasBaseVersion = do
+    let allTags = M.toList $ availableToolVersions dls GHC
+    forM allTags $ \(ver, tags) -> case any isBase tags of
+      False -> do
+        lift $ $(logError) [i|Base tag missing from GHC ver #{ver}|]
+        addError
+      True -> pure ()
+
+  isBase (Base _) = True
+  isBase _        = False

 validateTarballs :: ( Monad m
                    , MonadLogger m
@@ -161,7 +179,7 @@ validateTarballs dls = do

 where
  downloadAll dli = do
-    let settings = Settings True False
+    let settings = Settings True False Never Curl
    let runLogger = myLoggerT LoggerConfig { lcPrintDebug = True
                                           , colorOutter  = B.hPut stderr
                                           , rawOutter    = (\_ -> pure ())
--- a/app/ghcup/Main.hs
+++ b/app/ghcup/Main.hs
@@ -19,6 +19,7 @@ import           GHCup.Types
 import           GHCup.Utils
 import           GHCup.Utils.File
 import           GHCup.Utils.Logger
+import           GHCup.Utils.MegaParsec
 import           GHCup.Utils.Prelude
 import           GHCup.Version

@@ -32,11 +33,12 @@ import           Data.Bifunctor
 import           Data.Char
 import           Data.Either
 import           Data.Functor
-import           Data.List                      ( intercalate )
+import           Data.List                      ( intercalate, sort )
+import           Data.List.NonEmpty             (NonEmpty ((:|)))
 import           Data.Maybe
 import           Data.String.Interpolate
 import           Data.Text                      ( Text )
-import           Data.Versions
+import           Data.Versions           hiding ( str )
 import           Data.Void
 import           GHC.IO.Encoding
 import           Haskus.Utils.Variant.Excepts
@@ -73,6 +75,8 @@ data Options = Options
  , optCache     :: Bool
  , optUrlSource :: Maybe URI
  , optNoVerify  :: Bool
+  , optKeepDirs  :: KeepDirs
+  , optsDownloader :: Downloader
  -- commands
  , optCommand   :: Command
  }
@@ -89,9 +93,13 @@ data Command
  | ToolRequirements
  | ChangeLog ChangeLogOptions

-data ToolVersion = ToolVersion Version
+data ToolVersion = ToolVersion GHCTargetVersion -- target is ignored for cabal
                 | ToolTag Tag

+prettyToolVer :: ToolVersion -> String
+prettyToolVer (ToolVersion v') = T.unpack $ prettyTVer v'
+prettyToolVer (ToolTag t) = show t
+

 data InstallOptions = InstallOptions
  { instVer      :: Maybe ToolVersion
@@ -103,20 +111,31 @@ data SetGHCOptions = SetGHCOptions
  }

 data ListOptions = ListOptions
-  { lTool     :: Maybe Tool
-  , lCriteria :: Maybe ListCriteria
+  { lTool      :: Maybe Tool
+  , lCriteria  :: Maybe ListCriteria
+  , lRawFormat :: Bool
  }

 data RmOptions = RmOptions
-  { ghcVer :: Version
+  { ghcVer :: GHCTargetVersion
  }


-data CompileCommand = CompileGHC CompileOptions
-                    | CompileCabal CompileOptions
+data CompileCommand = CompileGHC GHCCompileOptions
+                    | CompileCabal CabalCompileOptions


-data CompileOptions = CompileOptions
+data GHCCompileOptions = GHCCompileOptions
+  { targetVer    :: Version
+  , bootstrapGhc :: Either Version (Path Abs)
+  , jobs         :: Maybe Int
+  , buildConfig  :: Maybe (Path Abs)
+  , patchDir     :: Maybe (Path Abs)
+  , crossTarget  :: Maybe Text
+  , addConfArgs  :: [Text]
+  }
+
+data CabalCompileOptions = CabalCompileOptions
  { targetVer    :: Version
  , bootstrapGhc :: Either Version (Path Abs)
  , jobs         :: Maybe Int
@@ -158,6 +177,31 @@ opts =
          (short 'n' <> long "no-verify" <> help
            "Skip tarball checksum verification"
          )
+    <*> option
+          (eitherReader keepOnParser)
+          (  long "keep"
+          <> metavar "<always|errors|never>"
+          <> help
+               "Keep build directories? (default: never)"
+          <> value Never
+          <> hidden
+          )
+    <*> option
+          (eitherReader downloaderParser)
+          (  long "downloader"
+#if defined(INTERNAL_DOWNLOADER)
+          <> metavar "<internal|curl|wget>"
+          <> help
+          "Downloader to use (default: internal)"
+          <> value Internal
+#else
+          <> metavar "<curl|wget>"
+          <> help
+          "Downloader to use (default: curl)"
+          <> value Curl
+#endif
+          <> hidden
+          )
    <*> com
 where
  parseUri s' =
@@ -309,6 +353,9 @@ listOpts =
            )
          )
        )
+    <*> switch
+          (short 'r' <> long "raw-format" <> help "More machine-parsable format"
+          )

 rmOpts :: Parser RmOptions
 rmOpts = RmOptions <$> versionArgument
@@ -341,7 +388,7 @@ compileP = subparser
      "ghc"
      (   CompileGHC
      <$> (info
-            (compileOpts <**> helper)
+            (ghcCompileOpts <**> helper)
            (  progDesc "Compile GHC from source"
            <> footerDoc (Just $ text compileFooter)
            )
@@ -351,7 +398,7 @@ compileP = subparser
       "cabal"
       (   CompileCabal
       <$> (info
-             (compileOpts <**> helper)
+             (cabalCompileOpts <**> helper)
             (  progDesc "Compile Cabal from source"
             <> footerDoc (Just $ text compileCabalFooter)
             )
@@ -364,9 +411,19 @@ compileP = subparser
  a self-contained "~/.ghcup/ghc/<ghcver>" directory
  and symlinks the ghc binaries to "~/.ghcup/bin/<binary>-<ghcver>".

+  This also allows building a cross-compiler. Consult the documentation
+  first: <https://gitlab.haskell.org/ghc/ghc/-/wikis/building/cross-compiling#configuring-the-build>
+
+ENV variables:
+  Various toolchain variables will be passed onto the ghc build system,
+  such as: CC, LD, OBJDUMP, NM, AR, RANLIB.
+
 Examples:
  ghcup compile ghc -j 4 -v 8.4.2 -b 8.2.2
-  ghcup compile ghc -j 4 -v 8.4.2 -b /usr/bin/ghc-8.2.2|]
+  # specify path to bootstrap ghc
+  ghcup compile ghc -j 4 -v 8.4.2 -b /usr/bin/ghc-8.2.2
+  # build cross compiler
+  ghcup compile ghc -j 4 -v 8.4.2 -b 8.2.2 -x armv7-unknown-linux-gnueabihf --config $(pwd)/build.mk -- --enable-unregisterised|]
  compileCabalFooter = [i|Discussion:
  Compiles and installs the specified Cabal version
  into "~/.ghcup/bin".
@@ -376,10 +433,24 @@ Examples:
  ghcup compile cabal -j 4 -v 3.2.0.0 -b /usr/bin/ghc-8.6.5|]


+ghcCompileOpts :: Parser GHCCompileOptions
+ghcCompileOpts =
+  (\CabalCompileOptions {..} crossTarget addConfArgs -> GHCCompileOptions { .. }
+    )
+    <$> cabalCompileOpts
+    <*> (optional
+          (option
+            str
+            (short 'x' <> long "cross-target" <> metavar "CROSS_TARGET" <> help
+              "Build cross-compiler for this platform"
+            )
+          )
+        )
+    <*> many (argument str (metavar "CONFIGURE_ARGS" <> help "Additional arguments to configure, prefix with '-- ' (longopts)"))

-compileOpts :: Parser CompileOptions
-compileOpts =
-  CompileOptions
+cabalCompileOpts :: Parser CabalCompileOptions
+cabalCompileOpts =
+  CabalCompileOptions
    <$> (option
          (eitherReader
            (bimap (const "Not a valid version") id . version . T.pack)
@@ -454,12 +525,12 @@ toolVersionArgument =
  argument (eitherReader toolVersionEither) (metavar "VERSION|TAG")


-versionArgument :: Parser Version
-versionArgument = argument (eitherReader versionEither) (metavar "VERSION")
+versionArgument :: Parser GHCTargetVersion
+versionArgument = argument (eitherReader tVersionEither) (metavar "VERSION")

-versionParser :: Parser Version
+versionParser :: Parser GHCTargetVersion
 versionParser = option
-  (eitherReader versionEither)
+  (eitherReader tVersionEither)
  (short 'v' <> long "version" <> metavar "VERSION" <> help "The target version"
  )

@@ -467,18 +538,20 @@ tagEither :: String -> Either String Tag
 tagEither s' = case fmap toLower s' of
  "recommended" -> Right Recommended
  "latest"      -> Right Latest
+  ('b':'a':'s':'e':'-':ver') -> case pvp (T.pack ver') of
+                                  Right x -> Right (Base x)
+                                  Left  _ -> Left [i|Invalid PVP version for base #{ver'}|]
  other         -> Left ([i|Unknown tag #{other}|])

-versionEither :: String -> Either String Version
-versionEither s' =
-  -- 'version' is a bit too lax and will parse typoed tags
-                   case readMaybe ((: []) . head $ s') :: Maybe Int of
-  Just _  -> bimap (const "Not a valid version") id . version . T.pack $ s'
-  Nothing -> Left "Not a valid version"
+
+tVersionEither :: String -> Either String GHCTargetVersion
+tVersionEither =
+  bimap (const "Not a valid version") id . MP.parse ghcTargetVerP "" . T.pack
+

 toolVersionEither :: String -> Either String ToolVersion
 toolVersionEither s' =
-  bimap id ToolTag (tagEither s') <|> bimap id ToolVersion (versionEither s')
+  bimap id ToolTag (tagEither s') <|> bimap id ToolVersion (tVersionEither s')


 toolParser :: String -> Either String Tool
@@ -495,6 +568,24 @@ criteriaParser s' | t == T.pack "installed" = Right ListInstalled
  where t = T.toLower (T.pack s')


+keepOnParser :: String -> Either String KeepDirs
+keepOnParser s' | t == T.pack "always" = Right Always
+                | t == T.pack "errors" = Right Errors
+                | t == T.pack "never"  = Right Never
+                | otherwise            = Left ("Unknown keep value: " <> s')
+  where t = T.toLower (T.pack s')
+
+
+downloaderParser :: String -> Either String Downloader
+downloaderParser s' | t == T.pack "curl"     = Right Curl
+                    | t == T.pack "wget"     = Right Wget
+#if defined(INTERNAL_DOWNLOADER)
+                    | t == T.pack "internal" = Right Internal
+#endif
+                    | otherwise = Left ("Unknown downloader value: " <> s')
+  where t = T.toLower (T.pack s')
+
+
 platformParser :: String -> Either String PlatformRequest
 platformParser s' = case MP.parse (platformP <* MP.eof) "" (T.pack s') of
  Right r -> pure r
@@ -554,24 +645,15 @@ platformParser s' = case MP.parse (platformP <* MP.eof) "" (T.pack s') of
        MP.setInput rest
        pure v

-  choice' []       = fail "Empty list"
-  choice' [x     ] = x
-  choice' (x : xs) = MP.try x <|> choice' xs

-  parseUntil :: MP.Parsec Void Text Text -> MP.Parsec Void Text Text
-  parseUntil p = do
-    (MP.try (MP.lookAhead p) $> mempty)
-      <|> (do
-            c  <- T.singleton <$> MP.anySingle
-            c2 <- parseUntil p
-            pure (c `mappend` c2)
-          )


 toSettings :: Options -> Settings
 toSettings Options {..} =
-  let cache    = optCache
-      noVerify = optNoVerify
+  let cache      = optCache
+      noVerify   = optNoVerify
+      keepDirs   = optKeepDirs
+      downloader = optsDownloader
  in  Settings { .. }


@@ -624,21 +706,31 @@ main = do
        <> help "Show the numeric version (for use in scripts)"
        <> hidden
        )
+  let listCommands = infoOption
+        "install set rm install-cabal list upgrade compile debug-info tool-requirements changelog"
+        (  long "list-commands"
+        <> help "List available commands for shell completion"
+        <> internal
+        )

  let main_footer = [i|Discussion:
  ghcup installs the Glasgow Haskell Compiler from the official
  release channels, enabling you to easily switch between different
-  versions.
+  versions. It maintains a self-contained ~/.ghcup directory.
+
+ENV variables:
+  * TMPDIR: where ghcup does the work (unpacking, building, ...)
+  * GHCUP_INSTALL_BASE_PREFIX: the base of ghcup (default: $HOME)

 Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]

  customExecParser
      (prefs showHelpOnError)
-      (info (opts <**> helper <**> versionHelp <**> numericVersionHelp)
+      (info (opts <**> helper <**> versionHelp <**> numericVersionHelp <**> listCommands)
            (footerDoc (Just $ text main_footer))
      )
    >>= \opt@Options {..} -> do
-          let settings = toSettings opt
+          let settings@Settings{..} = toSettings opt

          -- create ~/.ghcup dir
          ghcdir <- ghcupBaseDir
@@ -684,10 +776,7 @@ Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]
                    , TagNotFound
                    ]

-          let runListGHC =
-                runLogger
-                  . flip runReaderT settings
-                  . runE @'[FileDoesNotExistError]
+          let runListGHC = runE @'[] . runLogger

          let runRmGHC =
                runLogger . flip runReaderT settings . runE @'[NotInstalled]
@@ -752,9 +841,9 @@ Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]
          (GHCupInfo treq dls) <-
            ( runLogger
              . flip runReaderT settings
-              . runE @'[JSONError , DownloadFailed]
+              . runE @'[JSONError , DownloadFailed, FileDoesNotExistError]
              $ liftE
-              $ getDownloads (maybe GHCupURL OwnSource optUrlSource)
+              $ getDownloadsF (maybe GHCupURL OwnSource optUrlSource)
              )
              >>= \case
                    VRight r -> pure r
@@ -768,7 +857,7 @@ Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]
            Install (InstallOptions {..}) ->
              (runInstTool $ do
                  v <- liftE $ fromVersion dls instVer GHC
-                  liftE $ installGHCBin dls v instPlatform
+                  liftE $ installGHCBin dls (_tvVersion v) instPlatform -- FIXME: ugly sharing of tool version
                )
                >>= \case
                      VRight _ -> do
@@ -779,10 +868,18 @@ Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]
                          [i|GHC ver #{prettyVer v} already installed|]
                        pure ExitSuccess
                      VLeft (V (BuildFailed tmpdir e)) -> do
-                        runLogger
-                          ($(logError) [i|Build failed with #{e}
-Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues.|]
-                          )
+                        case keepDirs of
+                          Never -> runLogger ($(logError) [i|Build failed with #{e}|])
+                          _ -> runLogger ($(logError) [i|Build failed with #{e}
+Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues.
+Make sure to clean up #{tmpdir} afterwards.|])
+                        pure $ ExitFailure 3
+                      VLeft (V NoDownload) -> do
+
+                        runLogger $ do
+                          case instVer of
+                            Just iver -> $(logError) [i|No available GHC version for #{prettyToolVer iver}|]
+                            Nothing -> $(logError) [i|No available recommended GHC version|]
                        pure $ ExitFailure 3
                      VLeft e -> do
                        runLogger $ do
@@ -792,7 +889,7 @@ Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues
            InstallCabal (InstallOptions {..}) ->
              (runInstTool $ do
                  v <- liftE $ fromVersion dls instVer Cabal
-                  liftE $ installCabalBin dls v instPlatform
+                  liftE $ installCabalBin dls (_tvVersion v) instPlatform -- FIXME: ugly sharing of tool version
                )
                >>= \case
                      VRight _ -> do
@@ -802,6 +899,13 @@ Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues
                        runLogger $ $(logWarn)
                          [i|Cabal ver #{prettyVer v} already installed|]
                        pure ExitSuccess
+                      VLeft (V NoDownload) -> do
+
+                        runLogger $ do
+                          case instVer of
+                            Just iver -> $(logError) [i|No available Cabal version for #{prettyToolVer iver}|]
+                            Nothing -> $(logError) [i|No available recommended Cabal version|]
+                        pure $ ExitFailure 4
                      VLeft e -> do
                        runLogger $ do
                          $(logError) [i|#{e}|]
@@ -814,10 +918,10 @@ Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues
                  liftE $ setGHC v SetGHCOnly
                )
                >>= \case
-                      VRight v -> do
+                      VRight (GHCTargetVersion{..}) -> do
                        runLogger
                          $ $(logInfo)
-                              [i|GHC #{prettyVer v} successfully set as default version|]
+                              [i|GHC #{prettyVer _tvVersion} successfully set as default version#{maybe "" (" for cross target " <>) _tvTarget}|]
                        pure ExitSuccess
                      VLeft e -> do
                        runLogger ($(logError) [i|#{e}|])
@@ -825,11 +929,12 @@ Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues

            List (ListOptions {..}) ->
              (runListGHC $ do
-                  liftIO $ listVersions dls lTool lCriteria
+                  l <- listVersions dls lTool lCriteria
+                  pure l
                )
                >>= \case
                      VRight r -> do
-                        liftIO $ printListResult r
+                        liftIO $ printListResult lRawFormat r
                        pure ExitSuccess
                      VLeft e -> do
                        runLogger ($(logError) [i|#{e}|])
@@ -856,13 +961,14 @@ Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues
                        runLogger ($(logError) [i|#{e}|])
                        pure $ ExitFailure 8

-            Compile (CompileGHC CompileOptions {..}) ->
+            Compile (CompileGHC GHCCompileOptions {..}) ->
              (runCompileGHC $ liftE $ compileGHC dls
-                                                  targetVer
+                                                  (GHCTargetVersion crossTarget targetVer)
                                                  bootstrapGhc
                                                  jobs
                                                  buildConfig
                                                  patchDir
+                                                  addConfArgs
                )
                >>= \case
                      VRight _ -> do
@@ -874,17 +980,18 @@ Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues
                          [i|GHC ver #{prettyVer v} already installed|]
                        pure ExitSuccess
                      VLeft (V (BuildFailed tmpdir e)) -> do
-                        runLogger
-                          ($(logError) [i|Build failed with #{e}
+                        case keepDirs of
+                          Never -> runLogger ($(logError) [i|Build failed with #{e}
+Check the logs at ~/.ghcup/logs|])
+                          _ -> runLogger ($(logError) [i|Build failed with #{e}
 Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues.
-Make sure to clean up #{tmpdir} afterwards.|]
-                          )
+Make sure to clean up #{tmpdir} afterwards.|])
                        pure $ ExitFailure 9
                      VLeft e -> do
                        runLogger ($(logError) [i|#{e}|])
                        pure $ ExitFailure 9

-            Compile (CompileCabal CompileOptions {..}) ->
+            Compile (CompileCabal CabalCompileOptions {..}) ->
              (runCompileCabal $ do
                  liftE $ compileCabal dls targetVer bootstrapGhc jobs patchDir
                )
@@ -896,10 +1003,11 @@ Make sure to clean up #{tmpdir} afterwards.|]
                          )
                        pure ExitSuccess
                      VLeft (V (BuildFailed tmpdir e)) -> do
-                        runLogger
-                          ($(logError) [i|Build failed with #{e}
-Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues.|]
-                          )
+                        case keepDirs of
+                          Never -> runLogger ($(logError) [i|Build failed with #{e}|])
+                          _ -> runLogger ($(logError) [i|Build failed with #{e}
+Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues.
+Make sure to clean up #{tmpdir} afterwards.|])
                        pure $ ExitFailure 10
                      VLeft e -> do
                        runLogger ($(logError) [i|#{e}|])
@@ -954,7 +1062,7 @@ Check the logs at ~/.ghcup/logs and the build directory #{tmpdir} for more clues
                  ver' = maybe
                    (Right Latest)
                    (\case
-                      ToolVersion tv -> Left tv
+                      ToolVersion tv -> Left (_tvVersion tv) -- FIXME: ugly sharing of ToolVersion
                      ToolTag     t  -> Right t
                    )
                    clToolVer
@@ -991,47 +1099,75 @@ fromVersion :: Monad m
            => GHCupDownloads
            -> Maybe ToolVersion
            -> Tool
-            -> Excepts '[TagNotFound] m Version
+            -> Excepts '[TagNotFound] m GHCTargetVersion
 fromVersion av Nothing tool =
-  getRecommended av tool ?? TagNotFound Recommended tool
-fromVersion _ (Just (ToolVersion v)) _ = pure v
+  mkTVer <$> getRecommended av tool ?? TagNotFound Recommended tool
+fromVersion av (Just (ToolVersion v)) _ = do
+  case pvp $ prettyVer (_tvVersion v) of
+    Left _ -> pure v
+    Right (PVP (major' :|[minor'])) ->
+      case getLatestGHCFor (fromIntegral major') (fromIntegral minor') av of
+        Just v' -> pure $ GHCTargetVersion (_tvTarget v) v'
+        Nothing -> pure v
+    Right _ -> pure v
 fromVersion av (Just (ToolTag Latest)) tool =
-  getLatest av tool ?? TagNotFound Latest tool
+  mkTVer <$> getLatest av tool ?? TagNotFound Latest tool
 fromVersion av (Just (ToolTag Recommended)) tool =
-  getRecommended av tool ?? TagNotFound Recommended tool
+  mkTVer <$> getRecommended av tool ?? TagNotFound Recommended tool
+fromVersion av (Just (ToolTag (Base pvp''))) GHC =
+  mkTVer <$> getLatestBaseVersion av pvp'' ?? TagNotFound (Base pvp'') GHC
+fromVersion _ (Just (ToolTag t')) tool =
+  throwE $ TagNotFound t' tool


-printListResult :: [ListResult] -> IO ()
-printListResult lr = do
+printListResult :: Bool -> [ListResult] -> IO ()
+printListResult raw lr = do
  -- https://gitlab.haskell.org/ghc/ghc/issues/8118
  setLocaleEncoding utf8

  let
    formatted =
      gridString
-          [ column expand left def def
-          , column expand left def def
-          , column expand left def def
-          , column expand left def def
-          , column expand left def def
-          ]
+          (  (if raw then [] else [column expand left def def])
+          ++ [ column expand left def def
+             , column expand left def def
+             , column expand left def def
+             , column expand left def def
+             ]
+          )
+        . (\x -> if raw
+            then x
+            else [color Green "", "Tool", "Version", "Tags", "Notes"] : x
+          )
        $ fmap
            (\ListResult {..} ->
-              [ if
-                | lSet       -> (color Green "✔✔")
-                | lInstalled -> (color Green "✓")
-                | otherwise  -> (color Red "✗")
-              , fmap toLower . show $ lTool
-              , T.unpack . prettyVer $ lVer
-              , intercalate "," $ ((fmap . fmap) toLower . fmap show $ lTag)
-              , if fromSrc then (color Blue "compiled") else mempty
-              ]
+              let marks = if
+                    | lSet       -> (color Green "✔✔")
+                    | lInstalled -> (color Green "✓")
+                    | otherwise  -> (color Red "✗")
+              in  (if raw then [] else [marks])
+                    ++ [ fmap toLower . show $ lTool
+                       , case lCross of
+                           Nothing -> T.unpack . prettyVer $ lVer
+                           Just c  -> T.unpack (c <> "-" <> prettyVer lVer)
+                       , intercalate "," $ (fmap printTag $ sort lTag)
+                       , intercalate ","
+                       $  (if fromSrc then [color' Blue "compiled"] else mempty)
+                       ++ (if lStray then [color' Blue "stray"] else mempty)
+                       ]
            )
            lr
  putStrLn $ formatted
+ where
+  printTag Recommended        = color' Green "recommended"
+  printTag Latest             = color' Yellow "latest"
+  printTag (Base pvp'') = "base-" ++ T.unpack (prettyPVP pvp'')
+  printTag (UnknownTag t    ) = t
+  color' = case raw of
+    True  -> flip const
+    False -> color

-
-checkForUpdates :: (MonadIO m, MonadFail m, MonadLogger m)
+checkForUpdates :: (MonadThrow m, MonadIO m, MonadFail m, MonadLogger m)
                => GHCupDownloads
                -> m ()
 checkForUpdates dls = do
@@ -1057,7 +1193,7 @@ checkForUpdates dls = do

 where
  latestInstalled tool = (fmap lVer . lastMay)
-    <$> liftIO (listVersions dls (Just tool) (Just ListInstalled))
+    <$> (listVersions dls (Just tool) (Just ListInstalled))


 prettyDebugInfo :: DebugInfo -> String
--- a/ghcup-0.0.1.json
+++ b/ghcup-0.0.1.json
@@ -1958,7 +1958,7 @@
          "A_32": {
            "Linux_Alpine": {
              "unknown_versioning": {
-                "dlHash": "23779adb4cf4b314d0f8c66ee215ba6e74154c0768a573780475943544020bec",
+                "dlHash": "7a5f41646d06777e75636291a1855d60a0984552bbdf33c3d107565d302f38a4",
                "dlSubdir": "ghc-8.8.3",
                "dlUri": "https://github.com/redneb/ghc-alt-libc/releases/download/ghc-8.8.3-musl/ghc-8.8.3-i386-unknown-linux-musl.tar.xz"
              }
--- a/ghcup-0.0.2.json
+++ b/ghcup-0.0.2.json
--- a/ghcup.cabal
+++ b/ghcup.cabal
@@ -21,8 +21,8 @@ source-repository head
  type:     git
  location: https://gitlab.haskell.org/haskell/ghcup-hs.git

-flag Curl
-  description: Use curl instead of http-io-streams for download
+flag internal-downloader
+  description: Compile the internal downloader, which links against OpenSSL
  default:     False
  manual:      True

@@ -41,9 +41,6 @@ common ascii-string
 common async
  build-depends: async >=0.8

-common attoparsec
-  build-depends: attoparsec >=0.13
-
 common base
  build-depends: base >=4.12 && <5

@@ -230,7 +227,6 @@ library
    , aeson
    , ascii-string
    , async
-    , attoparsec
    , binary
    , bytestring
    , bz2
@@ -248,6 +244,7 @@ library
    , hpath-posix
    , language-bash
    , lzma
+    , megaparsec
    , monad-logger
    , mtl
    , optics
@@ -279,6 +276,9 @@ library

  exposed-modules:
    GHCup
+    GHCup.Data.GHCupDownloads
+    GHCup.Data.GHCupInfo
+    GHCup.Data.ToolRequirements
    GHCup.Download
    GHCup.Download.Utils
    GHCup.Errors
@@ -292,6 +292,7 @@ library
    GHCup.Utils.Dirs
    GHCup.Utils.File
    GHCup.Utils.Logger
+    GHCup.Utils.MegaParsec
    GHCup.Utils.Prelude
    GHCup.Utils.String.QQ
    GHCup.Utils.Version.QQ
@@ -301,15 +302,14 @@ library
  -- other-extensions:
  hs-source-dirs:  lib

-  if !flag(curl)
+  if flag(internal-downloader)
    import:
      , HsOpenSSL
      , http-io-streams
      , io-streams
      , terminal-progress-bar
    exposed-modules: GHCup.Download.IOStreams
-  else
-    cpp-options:     -DCURL
+    cpp-options:     -DINTERNAL_DOWNLOADER

 executable ghcup
  import:
@@ -344,6 +344,10 @@ executable ghcup
  hs-source-dirs:   app/ghcup
  default-language: Haskell2010

+  if flag(internal-downloader)
+    cpp-options:     -DINTERNAL_DOWNLOADER
+
+
 executable ghcup-gen
  import:
    config
@@ -372,9 +376,6 @@ executable ghcup-gen
  --
  main-is:          Main.hs
  other-modules:
-    GHCupDownloads
-    GHCupInfo
-    ToolRequirements
    Validate

  -- other-extensions:
--- a/lib/GHCup.hs
+++ b/lib/GHCup.hs
@@ -9,6 +9,7 @@
 {-# LANGUAGE TemplateHaskell       #-}
 {-# LANGUAGE TypeApplications      #-}
 {-# LANGUAGE TypeFamilies          #-}
+{-# LANGUAGE ViewPatterns          #-}

 module GHCup where

@@ -40,6 +41,7 @@ import           Data.ByteString                ( ByteString )
 import           Data.List
 import           Data.Maybe
 import           Data.String.Interpolate
+import           Data.Text                      ( Text )
 import           Data.Versions
 import           Data.Word8
 import           GHC.IO.Exception
@@ -52,11 +54,14 @@ import           Prelude                 hiding ( abs
                                                , writeFile
                                                )
 import           System.IO.Error
+import           System.Posix.Env.ByteString    ( getEnvironment )
 import           System.Posix.FilePath          ( getSearchPath )
 import           System.Posix.Files.ByteString

 import qualified Data.ByteString               as B
+import qualified Data.ByteString.Lazy          as BL
 import qualified Data.Map.Strict               as Map
+import qualified Data.Text                     as T
 import qualified Data.Text.Encoding            as E


@@ -93,45 +98,34 @@ installGHCBin :: ( MonadFail m
                   m
                   ()
 installGHCBin bDls ver mpfReq = do
+  let tver = (mkTVer ver)
  lift $ $(logDebug) [i|Requested to install GHC with #{ver}|]
-  whenM (liftIO $ toolAlreadyInstalled GHC ver)
+  whenM (liftIO $ ghcInstalled tver)
    $ (throwE $ AlreadyInstalled GHC ver)
-  Settings {..} <- lift ask
+  Settings {..}                <- lift ask
  pfreq@(PlatformRequest {..}) <- maybe (liftE $ platformRequest) pure mpfReq

  -- download (or use cached version)
-  dlinfo        <- lE $ getDownloadInfo GHC ver pfreq bDls
-  dl            <- liftE $ downloadCached dlinfo Nothing
+  dlinfo                       <- lE $ getDownloadInfo GHC ver pfreq bDls
+  dl                           <- liftE $ downloadCached dlinfo Nothing

  -- unpack
-  tmpUnpack     <- lift mkGhcupTmpDir
+  tmpUnpack                    <- lift mkGhcupTmpDir
  liftE $ unpackToDir tmpUnpack dl
  void $ liftIO $ darwinNotarization _rPlatform tmpUnpack

  -- prepare paths
-  ghcdir <- liftIO $ ghcupGHCDir ver
+  ghcdir <- liftIO $ ghcupGHCDir tver

  -- the subdir of the archive where we do the work
  let workdir = maybe tmpUnpack (tmpUnpack </>) (view dlSubdir dlinfo)

-  -- Be careful about cleanup. We must catch both pure exceptions
-  -- as well as async ones.
-  flip onException
-       (liftIO $ hideError doesNotExistErrorType $ deleteDirRecursive ghcdir)
-    $ catchAllE
-        (\es -> do
-          liftIO (hideError doesNotExistErrorType $ deleteDirRecursive ghcdir)
-            >> throwE (BuildFailed workdir es)
-        )
-    $ installGHC' workdir ghcdir
+  liftE $ runBuildAction tmpUnpack (Just ghcdir) (installGHC' workdir ghcdir)

-  -- only clean up dir if the build succeeded
-  liftIO $ deleteDirRecursive tmpUnpack
-
-  liftE $ postGHCInstall ver
+  liftE $ postGHCInstall tver

 where
-    -- | Install an unpacked GHC distribution. This only deals with the GHC build system and nothing else.
+  -- | Install an unpacked GHC distribution. This only deals with the GHC build system and nothing else.
  installGHC' :: (MonadLogger m, MonadIO m)
              => Path Abs      -- ^ Path to the unpacked GHC bindist (where the configure script resides)
              -> Path Abs      -- ^ Path to install to
@@ -172,15 +166,15 @@ installCabalBin :: ( MonadMask m
                     ()
 installCabalBin bDls ver mpfReq = do
  lift $ $(logDebug) [i|Requested to install cabal version #{ver}|]
-  Settings {..} <- lift ask
+  Settings {..}                <- lift ask
  pfreq@(PlatformRequest {..}) <- maybe (liftE $ platformRequest) pure mpfReq

  -- download (or use cached version)
-  dlinfo        <- lE $ getDownloadInfo Cabal ver pfreq bDls
-  dl            <- liftE $ downloadCached dlinfo Nothing
+  dlinfo                       <- lE $ getDownloadInfo Cabal ver pfreq bDls
+  dl                           <- liftE $ downloadCached dlinfo Nothing

  -- unpack
-  tmpUnpack     <- lift withGHCupTmpDir
+  tmpUnpack                    <- lift withGHCupTmpDir
  liftE $ unpackToDir tmpUnpack dl
  void $ liftIO $ darwinNotarization _rPlatform tmpUnpack

@@ -194,7 +188,7 @@ installCabalBin bDls ver mpfReq = do
  pure ()

 where
-    -- | Install an unpacked cabal distribution.
+  -- | Install an unpacked cabal distribution.
  installCabal' :: (MonadLogger m, MonadCatch m, MonadIO m)
                => Path Abs      -- ^ Path to the unpacked cabal bindist (where the executable resides)
                -> Path Abs      -- ^ Path to install to
@@ -226,11 +220,11 @@ installCabalBin bDls ver mpfReq = do
 -- Additionally creates a ~/.ghcup/share -> ~/.ghcup/ghc/<ver>/share symlink
 -- for `SetGHCOnly` constructor.
 setGHC :: (MonadLogger m, MonadThrow m, MonadFail m, MonadIO m)
-       => Version
+       => GHCTargetVersion
       -> SetGHC
-       -> Excepts '[NotInstalled] m Version
+       -> Excepts '[NotInstalled] m GHCTargetVersion
 setGHC ver sghc = do
-  let verBS = verToBS ver
+  let verBS = verToBS (_tvVersion ver)
  ghcdir <- liftIO $ ghcupGHCDir ver

  -- symlink destination
@@ -240,7 +234,7 @@ setGHC ver sghc = do
  -- first delete the old symlinks (this fixes compatibility issues
  -- with old ghcup)
  case sghc of
-    SetGHCOnly -> liftE $ rmPlain ver
+    SetGHCOnly -> liftE $ rmPlain (_tvTarget ver)
    SetGHC_XY  -> lift $ rmMajorSymlinks ver
    SetGHC_XYZ -> lift $ rmMinorSymlinks ver

@@ -250,9 +244,8 @@ setGHC ver sghc = do
    targetFile <- case sghc of
      SetGHCOnly -> pure file
      SetGHC_XY  -> do
-        major' <-
-          (\(mj, mi) -> E.encodeUtf8 $ intToText mj <> "." <> intToText mi)
-            <$> getGHCMajor ver
+        major' <- (\(mj, mi) -> E.encodeUtf8 $ intToText mj <> "." <> intToText mi)
+                     <$> getMajorMinorV (_tvVersion ver)
        parseRel (toFilePath file <> B.singleton _hyphen <> major')
      SetGHC_XYZ -> parseRel (toFilePath file <> B.singleton _hyphen <> verBS)

@@ -263,7 +256,7 @@ setGHC ver sghc = do
    liftIO $ createSymlink fullF destL

  -- create symlink for share dir
-  lift $ symlinkShareDir ghcdir verBS
+  when (isNothing . _tvTarget $ ver) $ lift $ symlinkShareDir ghcdir verBS

  pure ver

@@ -303,27 +296,41 @@ data ListCriteria = ListInstalled
 data ListResult = ListResult
  { lTool      :: Tool
  , lVer       :: Version
+  , lCross     :: Maybe Text -- ^ currently only for GHC
  , lTag       :: [Tag]
  , lInstalled :: Bool
-  , lSet       :: Bool
-  , fromSrc    :: Bool
+  , lSet       :: Bool -- ^ currently active version
+  , fromSrc    :: Bool -- ^ compiled from source
+  , lStray     :: Bool -- ^ not in download info
  }
-  deriving Show
+  deriving (Eq, Ord, Show)


-availableToolVersions :: GHCupDownloads -> Tool -> [(Version, [Tag])]
-availableToolVersions av tool = toListOf
-  (ix tool % to (fmap (\(v, vi) -> (v, (_viTags vi))) . Map.toList) % folded)
+availableToolVersions :: GHCupDownloads -> Tool -> Map.Map Version [Tag]
+availableToolVersions av tool = view
+  (at tool % non Map.empty % to (fmap (_viTags)))
  av


-listVersions :: GHCupDownloads
+-- | List all versions from the download info, as well as stray
+-- versions.
+listVersions :: (MonadThrow m, MonadLogger m, MonadIO m)
+             => GHCupDownloads
             -> Maybe Tool
             -> Maybe ListCriteria
-             -> IO [ListResult]
+             -> m [ListResult]
 listVersions av lt criteria = case lt of
  Just t -> do
-    filter' <$> forM (availableToolVersions av t) (toListResult t)
+    -- get versions from GHCupDownloads
+    let avTools = availableToolVersions av t
+    lr <- filter' <$> forM (Map.toList avTools) (liftIO . toListResult t)
+
+    case t of
+      -- append stray GHCs
+      GHC -> do
+        slr <- strayGHCs avTools
+        pure $ (sort (slr ++ lr))
+      _ -> pure lr
  Nothing -> do
    ghcvers   <- listVersions av (Just GHC) criteria
    cabalvers <- listVersions av (Just Cabal) criteria
@@ -331,21 +338,75 @@ listVersions av lt criteria = case lt of
    pure (ghcvers <> cabalvers <> ghcupvers)

 where
+  strayGHCs :: (MonadThrow m, MonadLogger m, MonadIO m)
+            => Map.Map Version [Tag]
+            -> m [ListResult]
+  strayGHCs avTools = do
+    ghcs <- getInstalledGHCs
+    fmap catMaybes $ forM ghcs $ \case
+      Right tver@GHCTargetVersion{ _tvTarget = Nothing, .. } -> do
+        case Map.lookup _tvVersion avTools of
+          Just _  -> pure Nothing
+          Nothing -> do
+            lSet    <- fmap (maybe False (\(GHCTargetVersion _ v ) -> v == _tvVersion)) $ ghcSet Nothing
+            fromSrc <- liftIO $ ghcSrcInstalled tver
+            pure $ Just $ ListResult
+              { lTool      = GHC
+              , lVer       = _tvVersion
+              , lCross     = Nothing
+              , lTag       = []
+              , lInstalled = True
+              , lStray     = maybe True (const False) (Map.lookup _tvVersion avTools)
+              , ..
+              }
+      Right tver@GHCTargetVersion{ .. } -> do
+        lSet    <- fmap (maybe False (\(GHCTargetVersion _ v ) -> v == _tvVersion)) $ ghcSet _tvTarget
+        fromSrc <- liftIO $ ghcSrcInstalled tver
+        pure $ Just $ ListResult
+          { lTool      = GHC
+          , lVer       = _tvVersion
+          , lCross     = _tvTarget
+          , lTag       = []
+          , lInstalled = True
+          , lStray     = True -- NOTE: cross currently cannot be installed via bindist
+          , ..
+          }
+      Left e -> do
+        $(logWarn)
+          [i|Could not parse version of stray directory #{toFilePath e}|]
+        pure Nothing
+
+  -- NOTE: this are not cross ones, because no bindists
  toListResult :: Tool -> (Version, [Tag]) -> IO ListResult
  toListResult t (v, tags) = case t of
    GHC -> do
-      lSet       <- fmap (maybe False (== v)) $ ghcSet
-      lInstalled <- ghcInstalled v
-      fromSrc    <- ghcSrcInstalled v
-      pure ListResult { lVer = v, lTag = tags, lTool = t, .. }
+      let tver = mkTVer v
+      lSet       <- fmap (maybe False (\(GHCTargetVersion _ v') -> v' == v)) $ ghcSet Nothing
+      lInstalled <- ghcInstalled tver
+      fromSrc    <- ghcSrcInstalled tver
+      pure ListResult { lVer = v, lCross = Nothing , lTag = tags, lTool = t, lStray = False, .. }
    Cabal -> do
      lSet <- fmap (== v) $ cabalSet
      let lInstalled = lSet
-      pure ListResult { lVer = v, lTag = tags, lTool = t, fromSrc = False, .. }
+      pure ListResult { lVer    = v
+                      , lCross  = Nothing
+                      , lTag    = tags
+                      , lTool   = t
+                      , fromSrc = False
+                      , lStray  = False
+                      , ..
+                      }
    GHCup -> do
      let lSet       = prettyPVP ghcUpVer == prettyVer v
      let lInstalled = lSet
-      pure ListResult { lVer = v, lTag = tags, lTool = t, fromSrc = False, .. }
+      pure ListResult { lVer    = v
+                      , lTag    = tags
+                      , lCross  = Nothing
+                      , lTool   = t
+                      , fromSrc = False
+                      , lStray  = False
+                      , ..
+                      }


  filter' :: [ListResult] -> [ListResult]
@@ -363,10 +424,10 @@ listVersions av lt criteria = case lt of

 -- | This function may throw and crash in various ways.
 rmGHCVer :: (MonadThrow m, MonadLogger m, MonadIO m, MonadFail m)
-         => Version
+         => GHCTargetVersion
         -> Excepts '[NotInstalled] m ()
 rmGHCVer ver = do
-  isSetGHC <- fmap (maybe False (== ver)) $ ghcSet
+  isSetGHC <- fmap (maybe False (== ver)) $ ghcSet (_tvTarget ver)
  dir      <- liftIO $ ghcupGHCDir ver
  let d' = toFilePath dir
  exists <- liftIO $ doesDirectoryExist dir
@@ -377,7 +438,7 @@ rmGHCVer ver = do
      -- this isn't atomic, order matters
      when isSetGHC $ do
        lift $ $(logInfo) [i|Removing ghc symlinks|]
-        liftE $ rmPlain ver
+        liftE $ rmPlain (_tvTarget ver)

      lift $ $(logInfo) [i|Removing directory recursively: #{d'}|]
      liftIO $ deleteDirRecursive dir
@@ -389,15 +450,15 @@ rmGHCVer ver = do
      -- first remove
      lift $ rmMajorSymlinks ver
      -- then fix them (e.g. with an earlier version)
-      (mj, mi) <- getGHCMajor ver
-      getGHCForMajor mj mi >>= mapM_ (\v -> liftE $ setGHC v SetGHC_XY)
+      (mj, mi) <- getMajorMinorV (_tvVersion ver)
+      getGHCForMajor mj mi (_tvTarget ver) >>= mapM_ (\v -> liftE $ setGHC v SetGHC_XY)

      liftIO
        $   ghcupBaseDir
        >>= hideError doesNotExistErrorType
        .   deleteFile
        .   (</> [rel|share|])
-    else throwE (NotInstalled GHC ver)
+    else throwE (NotInstalled GHC (ver ^. tvVersion % to prettyVer))



@@ -438,11 +499,12 @@ compileGHC :: ( MonadMask m
              , MonadFail m
              )
           => GHCupDownloads
-           -> Version                    -- ^ version to install
+           -> GHCTargetVersion           -- ^ version to install
           -> Either Version (Path Abs)  -- ^ version to bootstrap with
           -> Maybe Int                  -- ^ jobs
           -> Maybe (Path Abs)           -- ^ build config
-           -> Maybe (Path Abs)
+           -> Maybe (Path Abs)           -- ^ patch directory
+           -> [Text]                     -- ^ additional args to ./configure
           -> Excepts
                '[ AlreadyInstalled
                 , BuildFailed
@@ -459,13 +521,15 @@ compileGHC :: ( MonadMask m
                 ]
                m
                ()
-compileGHC dls tver bstrap jobs mbuildConfig patchdir = do
+compileGHC dls tver bstrap jobs mbuildConfig patchdir aargs = do
  lift $ $(logDebug) [i|Requested to compile: #{tver} with #{bstrap}|]
-  whenM (liftIO $ toolAlreadyInstalled GHC tver)
-        (throwE $ AlreadyInstalled GHC tver)
+  whenM (liftIO $ ghcInstalled tver)
+        (throwE $ AlreadyInstalled GHC (tver ^. tvVersion))

  -- download source tarball
-  dlInfo    <- preview (ix GHC % ix tver % viSourceDL % _Just) dls ?? NoDownload
+  dlInfo <-
+    preview (ix GHC % ix (tver ^. tvVersion) % viSourceDL % _Just) dls
+      ?? NoDownload
  dl        <- liftE $ downloadCached dlInfo Nothing

  -- unpack
@@ -480,32 +544,29 @@ compileGHC dls tver bstrap jobs mbuildConfig patchdir = do
  let workdir = maybe id (flip (</>)) (view dlSubdir dlInfo) $ tmpUnpack
  ghcdir <- liftIO $ ghcupGHCDir tver

-  -- Be careful about cleanup. We must catch both pure exceptions
-  -- as well as async ones.
-  flip onException
-       (liftIO $ hideError doesNotExistErrorType $ deleteDirRecursive ghcdir)
-    $ catchAllE
-        (\es ->
-          liftIO (hideError doesNotExistErrorType $ deleteDirRecursive ghcdir)
-            >> throwE (BuildFailed workdir es)
-        )
-    $ compile bghc ghcdir workdir
-  markSrcBuilt ghcdir workdir
-
-  -- only clean up dir if the build succeeded
-  liftIO $ deleteDirRecursive tmpUnpack
+  liftE $ runBuildAction
+    tmpUnpack
+    (Just ghcdir)
+    (compile bghc ghcdir workdir >> markSrcBuilt ghcdir workdir)

  reThrowAll GHCupSetError $ postGHCInstall tver
  pure ()

 where
-  defaultConf = [s|
+  defaultConf = case _tvTarget tver of
+                  Nothing -> [s|
 V=0
 BUILD_MAN = NO
 BUILD_SPHINX_HTML = NO
 BUILD_SPHINX_PDF = NO
-HADDOCK_DOCS = YES
-GhcWithLlvmCodeGen = YES|]
+HADDOCK_DOCS = YES|]
+                  Just _ -> [s|
+V=0
+BUILD_MAN = NO
+BUILD_SPHINX_HTML = NO
+BUILD_SPHINX_PDF = NO
+HADDOCK_DOCS = NO
+Stage1Only = YES|]

  compile :: (MonadCatch m, MonadLogger m, MonadIO m)
          => Either (Path Rel) (Path Abs)
@@ -513,6 +574,7 @@ GhcWithLlvmCodeGen = YES|]
          -> Path Abs
          -> Excepts
               '[ FileDoesNotExistError
+                , InvalidBuildConfig
                , PatchFailed
                , ProcessError
                , NotFoundInPATH
@@ -521,14 +583,14 @@ GhcWithLlvmCodeGen = YES|]
               ()
  compile bghc ghcdir workdir = do
    lift $ $(logInfo) [i|configuring build|]
+    liftE $ checkBuildConfig

    forM_ patchdir $ \dir -> liftE $ applyPatches dir workdir

-    -- force ld.bfd for build (others seem to misbehave, like lld from FreeBSD)
-    newEnv <- addToCurrentEnv [("LD", "ld.bfd")]
+    cEnv <- liftIO $ getEnvironment

    if
-      | tver >= [vver|8.8.0|] -> do
+      | (_tvVersion tver) >= [vver|8.8.0|] -> do
        bghcPath <- case bghc of
          Right ghc' -> pure ghc'
          Left  bver -> do
@@ -537,20 +599,32 @@ GhcWithLlvmCodeGen = YES|]
        lEM $ liftIO $ execLogged
          "./configure"
          False
-          ["--prefix=" <> toFilePath ghcdir]
+          (  ["--prefix=" <> toFilePath ghcdir]
+          ++ (maybe mempty
+                    (\x -> ["--target=" <> E.encodeUtf8 x])
+                    (_tvTarget tver)
+             )
+          ++ fmap E.encodeUtf8 aargs
+          )
          [rel|ghc-conf|]
          (Just workdir)
-          (Just (("GHC", toFilePath bghcPath) : newEnv))
+          (Just (("GHC", toFilePath bghcPath) : cEnv))
      | otherwise -> do
        lEM $ liftIO $ execLogged
          "./configure"
          False
-          [ "--prefix=" <> toFilePath ghcdir
-          , "--with-ghc=" <> either toFilePath toFilePath bghc
-          ]
+          (  [ "--prefix=" <> toFilePath ghcdir
+             , "--with-ghc=" <> either toFilePath toFilePath bghc
+             ]
+          ++ (maybe mempty
+                    (\x -> ["--target=" <> E.encodeUtf8 x])
+                    (_tvTarget tver)
+             )
+          ++ fmap E.encodeUtf8 aargs
+          )
          [rel|ghc-conf|]
          (Just workdir)
-          (Just newEnv)
+          (Just cEnv)

    case mbuildConfig of
      Just bc -> liftIOException
@@ -573,6 +647,30 @@ GhcWithLlvmCodeGen = YES|]

  build_mk workdir = workdir </> [rel|mk/build.mk|]

+  checkBuildConfig :: (MonadCatch m, MonadIO m)
+                   => Excepts
+                        '[FileDoesNotExistError , InvalidBuildConfig]
+                        m
+                        ()
+  checkBuildConfig = do
+    c <- case mbuildConfig of
+      Just bc -> do
+        BL.toStrict <$> liftIOException doesNotExistErrorType
+                                        (FileDoesNotExistError $ toFilePath bc)
+                                        (liftIO $ readFile bc)
+      Nothing -> pure defaultConf
+    let lines' = fmap T.strip . T.lines $ decUTF8Safe c
+
+   -- for cross, we need Stage1Only
+    case _tvTarget tver of
+      Just _ -> when (not $ elem "Stage1Only = YES" lines') $ throwE
+        (InvalidBuildConfig
+          [s|Cross compiling needs to be a Stage1 build, add "Stage1Only = YES" to your config!|]
+        )
+      Nothing -> pure ()
+
+
+

 compileCabal :: ( MonadReader Settings m
                , MonadResource m
@@ -613,7 +711,11 @@ compileCabal dls tver bghc jobs patchdir = do

  let workdir = maybe id (flip (</>)) (view dlSubdir dlInfo) $ tmpUnpack

-  reThrowAll (BuildFailed workdir) $ compile workdir
+
+  liftE $ runBuildAction
+    tmpUnpack
+    Nothing
+    (compile workdir)

  -- only clean up dir if the build succeeded
  liftIO $ deleteDirRecursive tmpUnpack
@@ -728,12 +830,12 @@ upgradeGHCup dls mtarget force = do
 -- | Creates ghc-x.y.z and ghc-x.y symlinks. This is used for
 -- both installing from source and bindist.
 postGHCInstall :: (MonadLogger m, MonadThrow m, MonadFail m, MonadIO m)
-               => Version
+               => GHCTargetVersion
               -> Excepts '[NotInstalled] m ()
-postGHCInstall ver = do
+postGHCInstall ver@GHCTargetVersion{..} = do
  void $ liftE $ setGHC ver SetGHC_XYZ

  -- Create ghc-x.y symlinks. This may not be the current
  -- version, create it regardless.
-  (mj, mi) <- liftIO $ getGHCMajor ver
-  getGHCForMajor mj mi >>= mapM_ (\v -> liftE $ setGHC v SetGHC_XY)
+  (mj, mi) <- getMajorMinorV _tvVersion
+  getGHCForMajor mj mi _tvTarget >>= mapM_ (\v -> liftE $ setGHC v SetGHC_XY)
--- a/lib/GHCup/Data/GHCupDownloads.hs
+++ b/lib/GHCup/Data/GHCupDownloads.hs
@@ -2,7 +2,7 @@
 {-# LANGUAGE QuasiQuotes       #-}


-module GHCupDownloads where
+module GHCup.Data.GHCupDownloads where

 import           GHCup.Types
 import           GHCup.Utils.Version.QQ
@@ -827,7 +827,7 @@ ghc_883_32_musl :: DownloadInfo
 ghc_883_32_musl = DownloadInfo
  [uri|https://github.com/redneb/ghc-alt-libc/releases/download/ghc-8.8.3-musl/ghc-8.8.3-i386-unknown-linux-musl.tar.xz|]
  (Just [rel|ghc-8.8.3|])
-  "23779adb4cf4b314d0f8c66ee215ba6e74154c0768a573780475943544020bec"
+  "7a5f41646d06777e75636291a1855d60a0984552bbdf33c3d107565d302f38a4"



@@ -951,6 +951,24 @@ cabal_3000_64_darwin = DownloadInfo
  Nothing
  "d4857e068560515e4cbb0e8ca124c370e07892f2a28804d87152834e5fe2b845"

+cabal_3000_64_freebsd :: DownloadInfo
+cabal_3000_64_freebsd = DownloadInfo
+  [uri|https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.0.0.0-x86_64-portbld-freebsd.tar.xz&dl=1|]
+  Nothing
+  "d97b6469ed612a1367ad1032d0722469ee5277668879694d7d4336233b937516"
+
+cabal_3000_32_alpine :: DownloadInfo
+cabal_3000_32_alpine = DownloadInfo
+  [uri|https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.0.0.0-i386-alpine-linux-musl.tar.xz&dl=1|]
+  Nothing
+  "a4191cd5a645b00e6a9c53abe6f3cb91fe700de7d7c520c9cb36ce8ec5c9919a"
+
+cabal_3000_64_alpine :: DownloadInfo
+cabal_3000_64_alpine = DownloadInfo
+  [uri|https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.0.0.0-x86_64-alpine-linux-musl.tar.xz&dl=1|]
+  Nothing
+  "7b35e5986aba4a40fc37141cbde26612bfc916e95a2d2ff35a413612d8c7cd3a"
+


    ---------------------
@@ -976,6 +994,24 @@ cabal_3200_64_darwin = DownloadInfo
  Nothing
  "9197c17d2ece0f934f5b33e323cfcaf486e4681952687bc3d249488ce3cbe0e9"

+cabal_3200_64_freebsd :: DownloadInfo
+cabal_3200_64_freebsd = DownloadInfo
+  [uri|https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.2.0.0-x86_64-portbld-freebsd.tar.xz&dl=1|]
+  Nothing
+  "e4dc00ab7fef51354e7624dd03e49c6bb684887fc95acb9b33bc52f357a5ef8c"
+
+cabal_3200_32_alpine :: DownloadInfo
+cabal_3200_32_alpine = DownloadInfo
+  [uri|https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.2.0.0-i386-alpine-linux-musl.tar.xz&dl=1|]
+  Nothing
+  "4aaa52fbc337ae1ef855a2aa2808186580b21ec36883aafec7473e7d899bc5ec"
+
+cabal_3200_64_alpine :: DownloadInfo
+cabal_3200_64_alpine = DownloadInfo
+  [uri|https://hasufell.de/d/d3e215db133e4fcaa61e/files/?p=/cabal-install-3.2.0.0-x86_64-alpine-linux-musl.tar.xz&dl=1|]
+  Nothing
+  "c1f3c21a5307cea8d2a0bd9a2eab9f56f3dd90e947ae64e231f909024980992b"
+



@@ -1026,7 +1062,7 @@ ghcupDownloads = M.fromList
    , M.fromList
      [ ( [vver|7.10.3|]
        , VersionInfo
-            []
+            [Base [pver|4.8.2.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/7.10.3/docs/html/users_guide/release-7-10-1.html|]
            )
@@ -1072,7 +1108,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.0.2|]
        , VersionInfo
-            []
+            [Base [pver|4.9.1.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.0.2/docs/html/users_guide/8.0.1-notes.html|]
            )
@@ -1118,7 +1154,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.2.2|]
        , VersionInfo
-            []
+            [Base [pver|4.10.1.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.2.2/docs/html/users_guide/8.2.2-notes.html|]
            )
@@ -1170,7 +1206,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.4.1|]
        , VersionInfo
-            []
+            [Base [pver|4.11.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.4.1/docs/html/users_guide/8.4.1-notes.html|]
            )
@@ -1209,7 +1245,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.4.2|]
        , VersionInfo
-            []
+            [Base [pver|4.11.1.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.4.2/docs/html/users_guide/8.4.2-notes.html|]
            )
@@ -1259,7 +1295,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.4.3|]
        , VersionInfo
-            []
+            [Base [pver|4.11.1.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.4.3/docs/html/users_guide/8.4.3-notes.html|]
            )
@@ -1308,7 +1344,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.4.4|]
        , VersionInfo
-            []
+            [Base [pver|4.11.1.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.4.4/docs/html/users_guide/8.4.4-notes.html|]
            )
@@ -1362,7 +1398,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.6.1|]
        , VersionInfo
-            []
+            [Base [pver|4.12.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.6.1/docs/html/users_guide/8.6.1-notes.html|]
            )
@@ -1412,7 +1448,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.6.2|]
        , VersionInfo
-            []
+            [Base [pver|4.12.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.6.2/docs/html/users_guide/8.6.2-notes.html|]
            )
@@ -1456,7 +1492,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.6.3|]
        , VersionInfo
-            []
+            [Base [pver|4.12.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.6.3/docs/html/users_guide/8.6.3-notes.html|]
            )
@@ -1510,7 +1546,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.6.4|]
        , VersionInfo
-            []
+            [Base [pver|4.12.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.6.4/docs/html/users_guide/8.6.4-notes.html|]
            )
@@ -1559,7 +1595,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.6.5|]
        , VersionInfo
-            []
+            [Base [pver|4.12.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.6.5/docs/html/users_guide/8.6.5-notes.html|]
            )
@@ -1612,7 +1648,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.8.1|]
        , VersionInfo
-            []
+            [Base [pver|4.13.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.8.1/docs/html/users_guide/8.8.1-notes.html|]
            )
@@ -1665,7 +1701,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.8.2|]
        , VersionInfo
-            []
+            [Base [pver|4.13.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.8.2/docs/html/users_guide/8.8.2-notes.html|]
            )
@@ -1718,7 +1754,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.8.3|]
        , VersionInfo
-            [Recommended]
+            [Recommended, Base [pver|4.13.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.8.3/docs/html/users_guide/8.8.3-notes.html|]
            )
@@ -1771,7 +1807,7 @@ ghcupDownloads = M.fromList
        )
      , ( [vver|8.10.1|]
        , VersionInfo
-            [Latest]
+            [Latest, Base [pver|4.14.0.0|]]
            (Just
              [uri|https://downloads.haskell.org/ghc/8.10.1/docs/html/users_guide/8.10.1-notes.html|]
            )
@@ -1889,7 +1925,9 @@ ghcupDownloads = M.fromList
                  [ ( Linux UnknownLinux
                    , M.fromList [(Nothing, cabal_3000_64_linux)]
                    )
-                  , (Darwin, M.fromList [(Nothing, cabal_3000_64_darwin)])
+                  , (Linux Alpine, M.fromList [(Nothing, cabal_3000_64_alpine)])
+                  , (Darwin      , M.fromList [(Nothing, cabal_3000_64_darwin)])
+                  , (FreeBSD, M.fromList [(Nothing, cabal_3000_64_freebsd)])
                  ]
                )
              , ( A_32
@@ -1897,6 +1935,7 @@ ghcupDownloads = M.fromList
                  [ ( Linux UnknownLinux
                    , M.fromList [(Nothing, cabal_3000_32_linux)]
                    )
+                  , (Linux Alpine, M.fromList [(Nothing, cabal_3000_32_alpine)])
                  ]
                )
              ]
@@ -1918,7 +1957,9 @@ ghcupDownloads = M.fromList
                  [ ( Linux UnknownLinux
                    , M.fromList [(Nothing, cabal_3200_64_linux)]
                    )
-                  , (Darwin, M.fromList [(Nothing, cabal_3200_64_darwin)])
+                  , (Linux Alpine, M.fromList [(Nothing, cabal_3200_64_alpine)])
+                  , (Darwin      , M.fromList [(Nothing, cabal_3200_64_darwin)])
+                  , (FreeBSD, M.fromList [(Nothing, cabal_3200_64_freebsd)])
                  ]
                )
              , ( A_32
@@ -1926,6 +1967,7 @@ ghcupDownloads = M.fromList
                  [ ( Linux UnknownLinux
                    , M.fromList [(Nothing, cabal_3200_32_linux)]
                    )
+                  , (Linux Alpine, M.fromList [(Nothing, cabal_3200_32_alpine)])
                  ]
                )
              ]
--- a/lib/GHCup/Data/GHCupInfo.hs
+++ b/lib/GHCup/Data/GHCupInfo.hs
@@ -1,7 +1,7 @@
-module GHCupInfo where
+module GHCup.Data.GHCupInfo where

-import           GHCupDownloads
-import           ToolRequirements
+import           GHCup.Data.GHCupDownloads
+import           GHCup.Data.ToolRequirements
 import           GHCup.Types


--- a/lib/GHCup/Data/ToolRequirements.hs
+++ b/lib/GHCup/Data/ToolRequirements.hs
@@ -1,10 +1,11 @@
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE QuasiQuotes       #-}

-module ToolRequirements where
+module GHCup.Data.ToolRequirements where

 import           GHCup.Types
 import           GHCup.Utils.String.QQ
+import           GHCup.Utils.Version.QQ

 import qualified Data.Map                      as M

@@ -61,6 +62,35 @@ toolRequirements = M.fromList
                )
              ]
            )
+          , ( Linux CentOS
+            , M.fromList
+              [ ( Nothing
+                , Requirements
+                  [ "gcc"
+                  , "gcc-c++"
+                  , "gmp"
+                  , "make"
+                  , "ncurses"
+                  , "ncurses-compat-libs"
+                  , "xz"
+                  , "perl"
+                  ]
+                  ""
+                ),
+              ( Just [vers|7|]
+                , Requirements
+                  [ "gcc"
+                  , "gcc-c++"
+                  , "gmp"
+                  , "make"
+                  , "ncurses"
+                  , "xz"
+                  , "perl"
+                  ]
+                  ""
+                )
+              ]
+            )
          , ( Darwin
            , M.fromList
              [ ( Nothing
--- a/lib/GHCup/Download.hs
+++ b/lib/GHCup/Download.hs
@@ -11,7 +11,7 @@

 module GHCup.Download where

-#if !defined(CURL)
+#if defined(INTERNAL_DOWNLOADER)
 import           GHCup.Download.IOStreams
 import           GHCup.Download.Utils
 #endif
@@ -35,18 +35,19 @@ import           Control.Monad.Reader
 import           Control.Monad.Trans.Resource
                                         hiding ( throwM )
 import           Data.Aeson
-#if !defined(CURL)
 import           Data.ByteString                ( ByteString )
+#if defined(INTERNAL_DOWNLOADER)
 import           Data.CaseInsensitive           ( CI )
 #endif
 import           Data.Maybe
 import           Data.String.Interpolate
 import           Data.Time.Clock
 import           Data.Time.Clock.POSIX
-#if !defined(CURL)
+#if defined(INTERNAL_DOWNLOADER)
 import           Data.Time.Format
 #endif
 import           Data.Versions
+import           Data.Word8
 import           GHC.IO.Exception
 import           HPath
 import           HPath.IO                      as HIO
@@ -57,12 +58,14 @@ import           Prelude                 hiding ( abs
                                                , writeFile
                                                )
 import           System.IO.Error
+import           System.Posix.Env.ByteString    ( getEnv )
 import           URI.ByteString

 import qualified Crypto.Hash.SHA256            as SHA256
+import qualified Data.ByteString               as BS
 import qualified Data.ByteString.Base16        as B16
 import qualified Data.ByteString.Lazy          as L
-#if !defined(CURL)
+#if defined(INTERNAL_DOWNLOADER)
 import qualified Data.CaseInsensitive          as CI
 import qualified Data.Map.Strict               as M
 import qualified Data.Text                     as T
@@ -82,6 +85,48 @@ import qualified System.Posix.RawFilePath.Directory
    ------------------


+-- | Like 'getDownloads', but tries to fall back to
+-- cached ~/.ghcup/cache/ghcup-<format-ver>.json
+getDownloadsF :: ( FromJSONKey Tool
+                 , FromJSONKey Version
+                 , FromJSON VersionInfo
+                 , MonadIO m
+                 , MonadCatch m
+                 , MonadLogger m
+                 , MonadThrow m
+                 , MonadFail m
+                 , MonadReader Settings m
+                 )
+              => URLSource
+              -> Excepts
+                   '[JSONError , DownloadFailed , FileDoesNotExistError]
+                   m
+                   GHCupInfo
+getDownloadsF urlSource = do
+  case urlSource of
+    GHCupURL ->
+      liftE
+        $ handleIO (\_ -> readFromCache)
+        $ catchE @_ @'[JSONError , FileDoesNotExistError]
+            (\(DownloadFailed _) -> readFromCache)
+        $ getDownloads urlSource
+    (OwnSource _) -> liftE $ getDownloads urlSource
+    (OwnSpec   _) -> liftE $ getDownloads urlSource
+ where
+  readFromCache = do
+    lift $ $(logWarn)
+      [i|Could not get download info, trying cached version (this may not be recent!)|]
+    let path = view pathL' ghcupURL
+    cacheDir  <- liftIO $ ghcupCacheDir
+    json_file <- (cacheDir </>) <$> urlBaseName path
+    bs        <-
+      handleIO' NoSuchThing
+                (\_ -> throwE $ FileDoesNotExistError (toFilePath json_file))
+      $ liftIO
+      $ readFile json_file
+    lE' JSONDecodeError $ eitherDecode' bs
+
+
 -- | Downloads the download information! But only if we need to ;P
 getDownloads :: ( FromJSONKey Tool
                , FromJSONKey Version
@@ -91,6 +136,7 @@ getDownloads :: ( FromJSONKey Tool
                , MonadLogger m
                , MonadThrow m
                , MonadFail m
+                , MonadReader Settings m
                )
             => URLSource
             -> Excepts '[JSONError , DownloadFailed] m GHCupInfo
@@ -116,7 +162,12 @@ getDownloads urlSource = do
  --
  -- Always save the local file with the mod time of the remote file.
  smartDl :: forall m1
-           . (MonadCatch m1, MonadIO m1, MonadFail m1, MonadLogger m1)
+           . ( MonadCatch m1
+             , MonadIO m1
+             , MonadFail m1
+             , MonadLogger m1
+             , MonadReader Settings m1
+             )
          => URI
          -> Excepts
               '[ FileDoesNotExistError
@@ -148,31 +199,38 @@ getDownloads urlSource = do
              Just modTime -> do
                fileMod <- liftIO $ getModificationTime json_file
                if modTime > fileMod
-                  then do
-                    bs <- liftE $ downloadBS uri'
-                    liftIO $ writeFileWithModTime modTime json_file bs
-                    pure bs
+                  then dlWithMod modTime json_file
                  else liftIO $ readFile json_file
              Nothing -> do
                lift $ $(logDebug) [i|Unable to get/parse Last-Modified header|]
-                liftIO $ deleteFile json_file
-                liftE $ downloadBS uri'
+                dlWithoutMod json_file
          else -- access in less than 5 minutes, re-use file
               liftIO $ readFile json_file
      else do
        liftIO $ createDirIfMissing newDirPerms cacheDir
        getModTime >>= \case
-          Just modTime -> do
-            bs <- liftE $ downloadBS uri'
-            liftIO $ writeFileWithModTime modTime json_file bs
-            pure bs
+          Just modTime -> dlWithMod modTime json_file
          Nothing -> do
+            -- although we don't know last-modified, we still save
+            -- it to a file, so we might use it in offline mode
            lift $ $(logDebug) [i|Unable to get/parse Last-Modified header|]
-            liftE $ downloadBS uri'
+            dlWithoutMod json_file

   where
+    dlWithMod modTime json_file = do
+      bs <- liftE $ downloadBS uri'
+      liftIO $ writeFileWithModTime modTime json_file bs
+      pure bs
+    dlWithoutMod json_file = do
+      bs <- liftE $ downloadBS uri'
+      liftIO $ hideError doesNotExistErrorType $ deleteFile json_file
+      liftIO $ writeFileL json_file (Just newFilePerms) bs
+      liftIO $ setModificationTime json_file (fromIntegral @Int 0)
+      pure bs
+
+
    getModTime = do
-#if defined(CURL)
+#if !defined(INTERNAL_DOWNLOADER)
      pure Nothing
 #else
      headers <-
@@ -271,12 +329,19 @@ download dli dest mfn
            (liftIO $ hideError doesNotExistErrorType $ deleteFile destFile)
              >> (throwE . DownloadFailed $ e)
          ) $ do
-#if defined(CURL)
-              liftE $ lEM @_ @'[ProcessError] $ liftIO $ exec "curl" True
-                ["-fL", "-o", toFilePath destFile , serializeURIRef' $ view dlUri dli] Nothing Nothing
-#else
-              (https, host, fullPath, port) <- liftE $ uriToQuadruple (view dlUri dli)
-              liftE $ downloadToFile https host fullPath port destFile
+              lift getDownloader >>= \case
+                Curl -> do
+                  o' <- liftIO getCurlOpts
+                  liftE $ lEM @_ @'[ProcessError] $ liftIO $ exec "curl" True
+                    (o' ++ ["-fL", "-o", toFilePath destFile, serializeURIRef' $ view dlUri dli]) Nothing Nothing
+                Wget -> do
+                  o' <- liftIO getWgetOpts
+                  liftE $ lEM @_ @'[ProcessError] $ liftIO $ exec "wget" True
+                    (o' ++ ["-O", toFilePath destFile , serializeURIRef' $ view dlUri dli]) Nothing Nothing
+#if defined(INTERNAL_DOWNLOADER)
+                Internal -> do
+                  (https, host, fullPath, port) <- liftE $ uriToQuadruple (view dlUri dli)
+                  liftE $ downloadToFile https host fullPath port destFile
 #endif

    liftE $ checkDigest dli destFile
@@ -329,7 +394,7 @@ downloadCached dli mfn = do


 -- | This is used for downloading the JSON.
-downloadBS :: (MonadCatch m, MonadIO m)
+downloadBS :: (MonadReader Settings m, MonadCatch m, MonadIO m, MonadLogger m)
           => URI
           -> Excepts
                '[ FileDoesNotExistError
@@ -356,18 +421,33 @@ downloadBS uri'
 where
  scheme = view (uriSchemeL' % schemeBSL') uri'
  path   = view pathL' uri'
-#if defined(CURL)
-  dl _ = do
-    let exe = [rel|curl|]
-        args = ["-sSfL", serializeURIRef' uri']
-    liftIO (executeOut exe args Nothing) >>= \case
-      CapturedProcess ExitSuccess stdout _ -> do
-        pure $ L.fromStrict stdout
-      CapturedProcess (ExitFailure i') _ _ -> throwE $ NonZeroExit i' (toFilePath exe) args
-#else
+#if defined(INTERNAL_DOWNLOADER)
  dl https = do
-    (_, host', fullPath', port') <- liftE $ uriToQuadruple uri'
-    liftE $ downloadBS' https host' fullPath' port'
+#else
+  dl _ = do
+#endif
+    lift $ $(logDebug) [i|downloading: #{serializeURIRef' uri'}|]
+    lift getDownloader >>= \case
+      Curl -> do
+        o' <- liftIO getCurlOpts
+        let exe = [rel|curl|]
+            args = o' ++ ["-sSfL", serializeURIRef' uri']
+        liftIO (executeOut exe args Nothing) >>= \case
+          CapturedProcess ExitSuccess stdout _ -> do
+            pure $ L.fromStrict stdout
+          CapturedProcess (ExitFailure i') _ _ -> throwE $ NonZeroExit i' (toFilePath exe) args
+      Wget -> do
+        o' <- liftIO getWgetOpts
+        let exe = [rel|wget|]
+            args = o' ++ ["-qO-", serializeURIRef' uri']
+        liftIO (executeOut exe args Nothing) >>= \case
+          CapturedProcess ExitSuccess stdout _ -> do
+            pure $ L.fromStrict stdout
+          CapturedProcess (ExitFailure i') _ _ -> throwE $ NonZeroExit i' (toFilePath exe) args
+#if defined(INTERNAL_DOWNLOADER)
+      Internal -> do
+        (_, host', fullPath', port') <- liftE $ uriToQuadruple uri'
+        liftE $ downloadBS' https host' fullPath' port'
 #endif


@@ -385,3 +465,19 @@ checkDigest dli file = do
    let eDigest = view dlHash dli
    when ((cDigest /= eDigest) && verify) $ throwE (DigestError cDigest eDigest)

+
+-- | Get additional curl args from env. This is an undocumented option.
+getCurlOpts :: IO [ByteString]
+getCurlOpts =
+  getEnv "GHCUP_CURL_OPTS" >>= \case
+    Just r  -> pure $ BS.split _space r
+    Nothing -> pure []
+
+
+-- | Get additional wget args from env. This is an undocumented option.
+getWgetOpts :: IO [ByteString]
+getWgetOpts =
+  getEnv "GHCUP_WGET_OPTS" >>= \case
+    Just r  -> pure $ BS.split _space r
+    Nothing -> pure []
+
--- a/lib/GHCup/Errors.hs
+++ b/lib/GHCup/Errors.hs
@@ -64,7 +64,7 @@ data AlreadyInstalled = AlreadyInstalled Tool Version

 -- | The tool is not installed. Some operations rely on a tool
 -- to be installed (such as setting the current GHC version).
-data NotInstalled = NotInstalled Tool Version
+data NotInstalled = NotInstalled Tool Text
  deriving Show

 -- | An executable was expected to be in PATH, but was not found.
@@ -104,6 +104,9 @@ data PatchFailed = PatchFailed
 data NoToolRequirements = NoToolRequirements
  deriving Show

+data InvalidBuildConfig = InvalidBuildConfig Text
+  deriving Show
+

    -------------------------
    --[ High-level errors ]--
--- a/lib/GHCup/Types.hs
+++ b/lib/GHCup/Types.hs
@@ -1,4 +1,6 @@
-{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE CPP               #-}
+{-# LANGUAGE DeriveGeneric     #-}
+{-# LANGUAGE OverloadedStrings #-}

 module GHCup.Types where

@@ -81,7 +83,9 @@ data VersionInfo = VersionInfo
 -- | A tag. These are currently attached to a version of a tool.
 data Tag = Latest
         | Recommended
-         deriving (Ord, Eq, Show)
+         | Base PVP
+         | UnknownTag String  -- ^ used for upwardscompat
+         deriving (Ord, Eq, Show) -- FIXME: manual JSON instance


 data Architecture = A_64
@@ -138,12 +142,26 @@ data URLSource = GHCupURL


 data Settings = Settings
-  { cache    :: Bool
-  , noVerify :: Bool
+  { cache      :: Bool
+  , noVerify   :: Bool
+  , keepDirs   :: KeepDirs
+  , downloader :: Downloader
  }
  deriving Show


+data KeepDirs = Always
+              | Errors
+              | Never
+  deriving (Eq, Show, Ord)
+
+data Downloader = Curl
+                | Wget
+#if defined(INTERNAL_DOWNLOADER)
+                | Internal
+#endif
+  deriving (Eq, Show, Ord)
+
 data DebugInfo = DebugInfo
  { diBaseDir  :: Path Abs
  , diBinDir   :: Path Abs
@@ -173,3 +191,23 @@ data PlatformRequest = PlatformRequest
  , _rVersion  :: Maybe Versioning
  }
  deriving (Eq, Show)
+
+
+-- | A GHC identified by the target platform triple
+-- and the version.
+data GHCTargetVersion = GHCTargetVersion
+  { _tvTarget  :: Maybe Text
+  , _tvVersion :: Version
+  }
+  deriving (Ord, Eq, Show)
+
+
+mkTVer :: Version -> GHCTargetVersion
+mkTVer = GHCTargetVersion Nothing
+
+
+-- | Assembles a path of the form: <target-triple>-<version>
+prettyTVer :: GHCTargetVersion -> Text
+prettyTVer (GHCTargetVersion (Just t) v') = t <> "-" <> prettyVer v'
+prettyTVer (GHCTargetVersion Nothing  v') = prettyVer v'
+
--- a/lib/GHCup/Types/JSON.hs
+++ b/lib/GHCup/Types/JSON.hs
@@ -37,11 +37,24 @@ deriveJSON defaultOptions { fieldLabelModifier = removeLensFieldLabel } ''Tool
 deriveJSON defaultOptions { fieldLabelModifier = removeLensFieldLabel } ''VSep
 deriveJSON defaultOptions { fieldLabelModifier = removeLensFieldLabel } ''VUnit
 deriveJSON defaultOptions { fieldLabelModifier = removeLensFieldLabel } ''VersionInfo
-deriveJSON defaultOptions { fieldLabelModifier = removeLensFieldLabel } ''Tag
 deriveJSON defaultOptions { fieldLabelModifier = removeLensFieldLabel } ''DownloadInfo
 deriveJSON defaultOptions { fieldLabelModifier = removeLensFieldLabel } ''GHCupInfo
 deriveJSON defaultOptions { fieldLabelModifier = removeLensFieldLabel } ''Requirements

+instance ToJSON Tag where
+  toJSON Latest             = String "Latest"
+  toJSON Recommended        = String "Recommended"
+  toJSON (Base       pvp'') = String ("base-" <> prettyPVP pvp'')
+  toJSON (UnknownTag x    ) = String (T.pack x)
+
+instance FromJSON Tag where
+  parseJSON = withText "Tag" $ \t -> case T.unpack t of
+    "Latest"                             -> pure Latest
+    "Recommended"                        -> pure Recommended
+    ('b' : 'a' : 's' : 'e' : '-' : ver') -> case pvp (T.pack ver') of
+      Right x -> pure $ Base x
+      Left  e -> fail . show $ e
+    x -> pure (UnknownTag x)

 instance ToJSON URI where
  toJSON = toJSON . decUTF8Safe . serializeURIRef'
@@ -143,6 +156,14 @@ instance FromJSONKey Version where
    Right x -> pure x
    Left  e -> fail $ "Failure in Version (FromJSONKey)" <> show e

+instance ToJSON PVP where
+  toJSON = toJSON . prettyPVP
+
+instance FromJSON PVP where
+  parseJSON = withText "PVP" $ \t -> case pvp t of
+    Right x -> pure x
+    Left  e -> fail $ "Failure in PVP (FromJSON)" <> show e
+
 instance ToJSONKey Tool where
  toJSONKey = genericToJSONKey defaultJSONKeyOptions

--- a/lib/GHCup/Types/Optics.hs
+++ b/lib/GHCup/Types/Optics.hs
@@ -19,6 +19,8 @@ makeLenses ''DownloadInfo
 makeLenses ''Tag
 makeLenses ''VersionInfo

+makeLenses ''GHCTargetVersion
+
 makeLenses ''GHCupInfo

 uriSchemeL' :: Lens' (URIRef Absolute) Scheme
--- a/lib/GHCup/Utils.hs
+++ b/lib/GHCup/Utils.hs
@@ -4,6 +4,7 @@
 {-# LANGUAGE OverloadedStrings     #-}
 {-# LANGUAGE QuasiQuotes           #-}
 {-# LANGUAGE TemplateHaskell       #-}
+{-# LANGUAGE ViewPatterns          #-}


 module GHCup.Utils
@@ -19,7 +20,9 @@ import           GHCup.Types.Optics
 import           GHCup.Types.JSON               ( )
 import           GHCup.Utils.Dirs
 import           GHCup.Utils.File
+import           GHCup.Utils.MegaParsec
 import           GHCup.Utils.Prelude
+import           GHCup.Utils.String.QQ

 import           Control.Applicative
 import           Control.Exception.Safe
@@ -29,11 +32,12 @@ import           Control.Monad.Fail             ( MonadFail )
 #endif
 import           Control.Monad.Logger
 import           Control.Monad.Reader
-import           Data.Attoparsec.ByteString
 import           Data.ByteString                ( ByteString )
+import           Data.Either
 import           Data.List
 import           Data.Maybe
 import           Data.String.Interpolate
+import           Data.Text                      ( Text )
 import           Data.Versions
 import           Data.Word8
 import           GHC.IO.Exception
@@ -51,6 +55,7 @@ import           System.Posix.FilePath          ( getSearchPath
                                                , takeFileName
                                                )
 import           System.Posix.Files.ByteString  ( readSymbolicLink )
+import           Text.Regex.Posix
 import           URI.ByteString

 import qualified Codec.Archive.Tar             as Tar
@@ -60,7 +65,7 @@ import qualified Codec.Compression.Lzma        as Lzma
 import qualified Data.ByteString               as B
 import qualified Data.Map.Strict               as Map
 import qualified Data.Text.Encoding            as E
-
+import qualified Text.Megaparsec               as MP



@@ -73,64 +78,69 @@ import qualified Data.Text.Encoding            as E

 -- | The symlink destination of a ghc tool.
 ghcLinkDestination :: ByteString -- ^ the tool, such as 'ghc', 'haddock' etc.
-                   -> Version
+                   -> GHCTargetVersion
                   -> ByteString
-ghcLinkDestination tool ver = "../ghc/" <> verToBS ver <> "/bin/" <> tool
-
-
-- | Extract the version part of the result of `ghcLinkDestination`.
-ghcLinkVersion :: MonadThrow m => ByteString -> m Version
-ghcLinkVersion = either (throwM . ParseError) pure . parseOnly parser
- where
-  parser    = string "../ghc/" *> verParser <* string "/bin/ghc"
-  verParser = many1' (notWord8 _slash) >>= \t ->
-    case
-        version (decUTF8Safe $ B.pack t)
-      of
-        Left  e -> fail $ show e
-        Right r -> pure r
+ghcLinkDestination tool ver =
+  "../ghc/" <> E.encodeUtf8 (prettyTVer ver) <> "/bin/" <> tool


 -- e.g. ghc-8.6.5
-rmMinorSymlinks :: (MonadIO m, MonadLogger m) => Version -> m ()
-rmMinorSymlinks ver = do
+rmMinorSymlinks :: (MonadIO m, MonadLogger m) => GHCTargetVersion -> m ()
+rmMinorSymlinks GHCTargetVersion {..} = do
  bindir <- liftIO $ ghcupBinDir
-  files  <- liftIO $ getDirsFiles' bindir
-  let myfiles =
-        filter (\x -> ("-" <> verToBS ver) `B.isSuffixOf` toFilePath x) files
-  forM_ myfiles $ \f -> do
+
+  files  <- liftIO $ findFiles'
+    bindir
+    (  maybe mempty (\x -> MP.chunk (x <> "-")) _tvTarget
+    *> parseUntil1 (MP.chunk $ prettyVer _tvVersion)
+    *> (MP.chunk $ prettyVer _tvVersion)
+    *> MP.eof
+    )
+
+  forM_ files $ \f -> do
    let fullF = (bindir </> f)
    $(logDebug) [i|rm -f #{toFilePath fullF}|]
    liftIO $ hideError doesNotExistErrorType $ deleteFile fullF

-- E.g. ghc, if this version is the set one.
-- This reads `ghcupGHCDir`.
+
+-- Removes the set ghc version for the given target, if any.
 rmPlain :: (MonadLogger m, MonadThrow m, MonadFail m, MonadIO m)
-        => Version
+  => Maybe Text -- ^ target
        -> Excepts '[NotInstalled] m ()
-rmPlain ver = do
-  files  <- liftE $ ghcToolFiles ver
-  bindir <- liftIO $ ghcupBinDir
-  forM_ files $ \f -> do
-    let fullF = (bindir </> f)
-    lift $ $(logDebug) [i|rm -f #{toFilePath fullF}|]
-    liftIO $ hideError doesNotExistErrorType $ deleteFile fullF
-  -- old ghcup
-  let hdc_file = (bindir </> [rel|haddock-ghc|])
-  lift $ $(logDebug) [i|rm -f #{toFilePath hdc_file}|]
-  liftIO $ hideError doesNotExistErrorType $ deleteFile hdc_file
+rmPlain target = do
+  mtv <- ghcSet target
+  forM_ mtv $ \tv -> do
+    files  <- liftE $ ghcToolFiles tv
+    bindir <- liftIO $ ghcupBinDir
+    forM_ files $ \f -> do
+      let fullF = (bindir </> f)
+      lift $ $(logDebug) [i|rm -f #{toFilePath fullF}|]
+      liftIO $ hideError doesNotExistErrorType $ deleteFile fullF
+    -- old ghcup
+    let hdc_file = (bindir </> [rel|haddock-ghc|])
+    lift $ $(logDebug) [i|rm -f #{toFilePath hdc_file}|]
+    liftIO $ hideError doesNotExistErrorType $ deleteFile hdc_file
+

 -- e.g. ghc-8.6
-rmMajorSymlinks :: (MonadLogger m, MonadIO m) => Version -> m ()
-rmMajorSymlinks ver = do
-  (mj, mi) <- liftIO $ getGHCMajor ver
-  let v' = E.encodeUtf8 $ intToText mj <> "." <> intToText mi
+rmMajorSymlinks :: (MonadThrow m, MonadLogger m, MonadIO m)
+                => GHCTargetVersion
+                -> m ()
+rmMajorSymlinks GHCTargetVersion {..} = do
+  (mj, mi) <- getMajorMinorV _tvVersion
+  let v' = intToText mj <> "." <> intToText mi

  bindir <- liftIO ghcupBinDir

-  files  <- liftIO $ getDirsFiles' bindir
-  let myfiles = filter (\x -> ("-" <> v') `B.isSuffixOf` toFilePath x) files
-  forM_ myfiles $ \f -> do
+  files  <- liftIO $ findFiles'
+    bindir
+    (  maybe mempty (\x -> MP.chunk (x <> "-")) _tvTarget
+    *> parseUntil1 (MP.chunk v')
+    *> MP.chunk v'
+    *> MP.eof
+    )
+
+  forM_ files $ \f -> do
    let fullF = (bindir </> f)
    $(logDebug) [i|rm -f #{toFilePath fullF}|]
    liftIO $ hideError doesNotExistErrorType $ deleteFile fullF
@@ -143,33 +153,61 @@ rmMajorSymlinks ver = do
    -----------------------------------


-toolAlreadyInstalled :: Tool -> Version -> IO Bool
-toolAlreadyInstalled tool ver = case tool of
-  GHC   -> ghcInstalled ver
-  Cabal -> cabalInstalled ver
-  GHCup -> pure True
-
-
-ghcInstalled :: Version -> IO Bool
+ghcInstalled :: GHCTargetVersion -> IO Bool
 ghcInstalled ver = do
  ghcdir <- ghcupGHCDir ver
  doesDirectoryExist ghcdir


-ghcSrcInstalled :: Version -> IO Bool
+ghcSrcInstalled :: GHCTargetVersion -> IO Bool
 ghcSrcInstalled ver = do
  ghcdir <- ghcupGHCDir ver
  doesFileExist (ghcdir </> ghcUpSrcBuiltFile)


-ghcSet :: (MonadIO m, MonadThrow m) => m (Maybe Version)
-ghcSet = do
-  ghcBin <- (</> [rel|ghc|]) <$> liftIO ghcupBinDir
+ghcSet :: (MonadThrow m, MonadIO m)
+       => Maybe Text   -- ^ the target of the GHC version, if any
+                       --  (e.g. armv7-unknown-linux-gnueabihf)
+       -> m (Maybe GHCTargetVersion)
+ghcSet mtarget = do
+  ghc    <- parseRel $ E.encodeUtf8 (maybe "ghc" (<> "-ghc") mtarget)
+  ghcBin <- (</> ghc) <$> liftIO ghcupBinDir

  -- link destination is of the form ../ghc/<ver>/bin/ghc
+  -- for old ghcup, it is ../ghc/<ver>/bin/ghc-<ver>
  liftIO $ handleIO' NoSuchThing (\_ -> pure $ Nothing) $ do
    link <- readSymbolicLink $ toFilePath ghcBin
    Just <$> ghcLinkVersion link
+ where
+  ghcLinkVersion :: MonadThrow m => ByteString -> m GHCTargetVersion
+  ghcLinkVersion bs = do
+    t <- throwEither $ E.decodeUtf8' bs
+    throwEither $ MP.parse parser "" t
+   where
+    parser =
+      MP.chunk "../ghc/"
+        *> (do
+             r    <- parseUntil1 (MP.chunk "/")
+             rest <- MP.getInput
+             MP.setInput r
+             x <- ghcTargetVerP
+             MP.setInput rest
+             pure x
+           )
+        <* MP.chunk "/"
+        <* MP.takeRest
+        <* MP.eof
+
+
+-- | Get all installed GHCs by reading ~/.ghcup/ghc/<dir>.
+-- If a dir cannot be parsed, returns left.
+getInstalledGHCs :: MonadIO m => m [Either (Path Rel) GHCTargetVersion]
+getInstalledGHCs = do
+  ghcdir <- liftIO $ ghcupGHCBaseDir
+  fs     <- liftIO $ hideErrorDef [NoSuchThing] [] $ getDirsFiles' ghcdir
+  forM fs $ \f -> case parseGHCupGHCDir f of
+    Right r -> pure $ Right r
+    Left  _ -> pure $ Left f


 cabalInstalled :: Version -> IO Bool
@@ -193,33 +231,49 @@ cabalSet = do
    -----------------------------------------


-- | We assume GHC is in semver format. I hope it is.
-getGHCMajor :: MonadThrow m => Version -> m (Int, Int)
-getGHCMajor ver = do
-  SemVer {..} <- throwEither (semver $ prettyVer ver)
-  pure (fromIntegral _svMajor, fromIntegral _svMinor)
+getMajorMinorV :: MonadThrow m => Version -> m (Int, Int)
+getMajorMinorV Version {..} = case _vChunks of
+  ([Digits x] : [Digits y] : _) -> pure (fromIntegral x, fromIntegral y)
+  _ -> throwM $ ParseError "Could not parse X.Y from version"
+
+
+matchMajor :: Version -> Int -> Int -> Bool
+matchMajor v' major' minor' = case getMajorMinorV v' of
+  Just (x, y) -> x == major' && y == minor'
+  Nothing     -> False


 -- | Get the latest installed full GHC version that satisfies X.Y.
 -- This reads `ghcupGHCBaseDir`.
 getGHCForMajor :: (MonadIO m, MonadThrow m)
-               => Int -- ^ major version component
-               -> Int -- ^ minor version component
-               -> m (Maybe Version)
-getGHCForMajor major' minor' = do
-  p       <- liftIO $ ghcupGHCBaseDir
-  ghcs    <- liftIO $ getDirsFiles' p
-  semvers <- forM ghcs $ \ghc ->
-    throwEither . semver =<< (throwEither . E.decodeUtf8' . toFilePath $ ghc)
-  mapM (throwEither . version)
-    . fmap prettySemVer
+               => Int        -- ^ major version component
+               -> Int        -- ^ minor version component
+               -> Maybe Text -- ^ the target triple
+               -> m (Maybe GHCTargetVersion)
+getGHCForMajor major' minor' mt = do
+  ghcs <- rights <$> getInstalledGHCs
+
+  pure
    . lastMay
-    . sort
+    . sortBy (\x y -> compare (_tvVersion x) (_tvVersion y))
    . filter
-        (\SemVer {..} ->
-          fromIntegral _svMajor == major' && fromIntegral _svMinor == minor'
+        (\GHCTargetVersion {..} ->
+          _tvTarget == mt && matchMajor _tvVersion major' minor'
        )
-    $ semvers
+    $ ghcs
+
+
+-- | Get the latest available ghc for X.Y major version.
+getLatestGHCFor :: Int -- ^ major version component
+                -> Int -- ^ minor version component
+                -> GHCupDownloads
+                -> Maybe Version
+getLatestGHCFor major' minor' dls = do
+  join
+    . fmap (lastMay . filter (\v -> matchMajor v major' minor'))
+    . preview (ix GHC % to Map.keys)
+    $ dls
+



@@ -265,7 +319,8 @@ unpackToDir dest av = do

 -- | Get the tool version that has this tag. If multiple have it,
 -- picks the greatest version.
-getTagged :: Tag -> AffineFold (Map.Map Version VersionInfo) (Version, VersionInfo)
+getTagged :: Tag
+          -> AffineFold (Map.Map Version VersionInfo) (Version, VersionInfo)
 getTagged tag =
  ( to (Map.filter (\VersionInfo {..} -> elem tag _viTags))
  % to Map.toDescList
@@ -279,6 +334,12 @@ getRecommended :: GHCupDownloads -> Tool -> Maybe Version
 getRecommended av tool = headOf (ix tool % getTagged Recommended % to fst) $ av


+-- | Gets the latest GHC with a given base version.
+getLatestBaseVersion :: GHCupDownloads -> PVP -> Maybe Version
+getLatestBaseVersion av pvpVer =
+  headOf (ix GHC % getTagged (Base pvpVer) % to fst) av
+
+

    -----------------------
    --[ Settings Getter ]--
@@ -289,6 +350,10 @@ getCache :: MonadReader Settings m => m Bool
 getCache = ask <&> cache


+getDownloader :: MonadReader Settings m => m Downloader
+getDownloader = ask <&> downloader
+
+

    -------------
    --[ Other ]--
@@ -302,12 +367,12 @@ urlBaseName = parseRel . snd . B.breakEnd (== _slash) . urlDecode False


 -- Get tool files from '~/.ghcup/bin/ghc/<ver>/bin/*'
-- while ignoring *-<ver> symlinks.
+-- while ignoring *-<ver> symlinks and accounting for cross triple prefix.
 --
 -- Returns unversioned relative files, e.g.:
 --   ["hsc2hs","haddock","hpc","runhaskell","ghc","ghc-pkg","ghci","runghc","hp2ps"]
 ghcToolFiles :: (MonadThrow m, MonadFail m, MonadIO m)
-             => Version
+             => GHCTargetVersion
             -> Excepts '[NotInstalled] m [Path Rel]
 ghcToolFiles ver = do
  ghcdir <- liftIO $ ghcupGHCDir ver
@@ -315,18 +380,28 @@ ghcToolFiles ver = do

  -- fail if ghc is not installed
  whenM (fmap not $ liftIO $ doesDirectoryExist ghcdir)
-        (throwE (NotInstalled GHC ver))
+        (throwE (NotInstalled GHC (prettyTVer ver)))

-  files         <- liftIO $ getDirsFiles' bindir
+  files    <- liftIO $ getDirsFiles' bindir
  -- figure out the <ver> suffix, because this might not be `Version` for
  -- alpha/rc releases, but x.y.a.somedate.
+
+  -- for cross, this won't be "ghc", but e.g.
+  -- "armv7-unknown-linux-gnueabihf-ghc"
+  [ghcbin] <- liftIO $ findFiles
+    bindir
+    (makeRegexOpts compExtended
+                   execBlank
+                   ([s|^([a-zA-Z0-9_-]*[a-zA-Z0-9_]-)?ghc$|] :: ByteString)
+    )
+
  (Just symver) <-
-    (B.stripPrefix "ghc-" . takeFileName)
-      <$> (liftIO $ readSymbolicLink $ toFilePath (bindir </> [rel|ghc|]))
+    (B.stripPrefix (toFilePath ghcbin <> "-") . takeFileName)
+      <$> (liftIO $ readSymbolicLink $ toFilePath (bindir </> ghcbin))
  when (B.null symver)
       (throwIO $ userError $ "Fatal: ghc symlink target is broken")

-  pure $ filter (\x -> not $ symver `B.isSuffixOf` toFilePath x) files
+  pure . filter (\x -> not $ symver `B.isSuffixOf` toFilePath x) $ files


 -- | This file, when residing in ~/.ghcup/ghc/<ver>/ signals that
@@ -377,10 +452,42 @@ darwinNotarization _ _ = pure $ Right ()
 getChangeLog :: GHCupDownloads -> Tool -> Either Version Tag -> Maybe URI
 getChangeLog dls tool (Left v') =
  preview (ix tool % ix v' % viChangeLog % _Just) dls
-getChangeLog dls tool (Right tag) = preview
-  ( ix tool
-  % getTagged tag
-  % to snd
-  % viChangeLog
-  % _Just
-  ) dls
+getChangeLog dls tool (Right tag) =
+  preview (ix tool % getTagged tag % to snd % viChangeLog % _Just) dls
+
+
+-- | Execute a build action while potentially cleaning up:
+--
+--   1. the build directory, depending on the KeepDirs setting
+--   2. the install destination, depending on whether the build failed
+runBuildAction :: (Show (V e), MonadReader Settings m, MonadIO m, MonadMask m)
+               => Path Abs          -- ^ build directory
+               -> Maybe (Path Abs)  -- ^ install location (e.g. for GHC)
+               -> Excepts e m ()
+               -> Excepts '[BuildFailed] m ()
+runBuildAction bdir instdir action = do
+  Settings {..} <- lift ask
+  flip
+      onException
+      (do
+        forM_ instdir $ \dir ->
+          liftIO $ hideError doesNotExistErrorType $ deleteDirRecursive dir
+        when (keepDirs == Never)
+          $ liftIO
+          $ hideError doesNotExistErrorType
+          $ deleteDirRecursive bdir
+      )
+    $ catchAllE
+        (\es -> do
+          forM_ instdir $ \dir ->
+            liftIO $ hideError doesNotExistErrorType $ deleteDirRecursive dir
+          when (keepDirs == Never)
+            $ liftIO
+            $ hideError doesNotExistErrorType
+            $ deleteDirRecursive bdir
+          throwE (BuildFailed bdir es)
+        )
+    $ action
+
+  when (keepDirs == Never || keepDirs == Errors) $ liftIO $ deleteDirRecursive
+    bdir
--- a/lib/GHCup/Utils/Dirs.hs
+++ b/lib/GHCup/Utils/Dirs.hs
@@ -1,10 +1,13 @@
 {-# LANGUAGE OverloadedStrings     #-}
 {-# LANGUAGE QuasiQuotes           #-}
+{-# LANGUAGE ViewPatterns          #-}

 module GHCup.Utils.Dirs where


+import           GHCup.Types
 import           GHCup.Types.JSON               ( )
+import           GHCup.Utils.MegaParsec
 import           GHCup.Utils.Prelude

 import           Control.Applicative
@@ -13,7 +16,6 @@ import           Control.Monad
 import           Control.Monad.Reader
 import           Control.Monad.Trans.Resource
 import           Data.Maybe
-import           Data.Versions
 import           HPath
 import           HPath.IO
 import           Optics
@@ -27,8 +29,10 @@ import           System.Posix.Env.ByteString    ( getEnv
 import           System.Posix.Temp.ByteString   ( mkdtemp )

 import qualified Data.ByteString.UTF8          as UTF8
+import qualified Data.Text.Encoding            as E
 import qualified System.Posix.FilePath         as FP
 import qualified System.Posix.User             as PU
+import qualified Text.Megaparsec               as MP



@@ -37,6 +41,7 @@ import qualified System.Posix.User             as PU
    -------------------------


+-- | ~/.ghcup by default
 ghcupBaseDir :: IO (Path Abs)
 ghcupBaseDir = do
  bdir <- getEnv "GHCUP_INSTALL_BASE_PREFIX" >>= \case
@@ -44,16 +49,30 @@ ghcupBaseDir = do
    Nothing -> liftIO getHomeDirectory
  pure (bdir </> [rel|.ghcup|])

+
+-- | ~/.ghcup/ghc by default.
 ghcupGHCBaseDir :: IO (Path Abs)
 ghcupGHCBaseDir = ghcupBaseDir <&> (</> [rel|ghc|])

-ghcupGHCDir :: Version -> IO (Path Abs)
+
+-- | Gets '~/.ghcup/ghc/<ghcupGHCDir>'.
+-- The dir may be of the form
+--   * armv7-unknown-linux-gnueabihf-8.8.3
+--   * 8.8.4
+ghcupGHCDir :: GHCTargetVersion -> IO (Path Abs)
 ghcupGHCDir ver = do
  ghcbasedir <- ghcupGHCBaseDir
-  verdir     <- parseRel (verToBS ver)
+  verdir     <- parseRel $ E.encodeUtf8 (prettyTVer ver)
  pure (ghcbasedir </> verdir)


+-- | See 'ghcupToolParser'.
+parseGHCupGHCDir :: MonadThrow m => Path Rel -> m GHCTargetVersion
+parseGHCupGHCDir (toFilePath -> f) = do
+  fp <- throwEither $ E.decodeUtf8' f
+  throwEither $ MP.parse ghcTargetVerP "" fp
+
+
 ghcupBinDir :: IO (Path Abs)
 ghcupBinDir = ghcupBaseDir <&> (</> [rel|bin|])

--- a/lib/GHCup/Utils/File.hs
+++ b/lib/GHCup/Utils/File.hs
@@ -18,6 +18,8 @@ import           Data.Foldable
 import           Data.Functor
 import           Data.IORef
 import           Data.Maybe
+import           Data.Text                      ( Text )
+import           Data.Void
 import           GHC.Foreign                    ( peekCStringLen )
 import           GHC.IO.Encoding                ( getLocaleEncoding )
 import           GHC.IO.Exception
@@ -39,10 +41,12 @@ import "unix"    System.Posix.IO.ByteString
                                         hiding ( openFd )
 import           System.Posix.Process           ( ProcessStatus(..) )
 import           System.Posix.Types
+import           Text.Regex.Posix


 import qualified Control.Exception             as EX
 import qualified Data.Text                     as T
+import qualified Data.Text.Encoding            as E
 import qualified System.Posix.Process.ByteString
                                               as SPPB
 import           Streamly.External.Posix.DirStream
@@ -51,12 +55,14 @@ import qualified Streamly.Internal.Memory.ArrayStream
 import qualified Streamly.FileSystem.Handle    as FH
 import qualified Streamly.Internal.Data.Unfold as SU
 import qualified Streamly.Prelude              as S
+import qualified Text.Megaparsec               as MP
 import qualified Data.ByteString               as BS
 import qualified Data.ByteString.Lazy          as L
 import qualified "unix-bytestring" System.Posix.IO.ByteString
                                               as SPIB


+
 -- | Bool signals whether the regions should be cleaned.
 data StopThread = StopThread Bool
  deriving Show
@@ -199,6 +205,7 @@ execLogged exe spath args lfile chdir env = do
    lineAction ref rs bs' = do
      modifyIORef' ref (swapRegs bs')
      regs <- readIORef ref
+      void $ SPIB.fdWrite fileFd (bs' <> "\n")
      forM (zip regs rs) $ \(bs, r) -> do
        setConsoleRegion r $ do
          w <- consoleWidth
@@ -210,8 +217,6 @@ execLogged exe spath args lfile chdir env = do
            . trim w
            . (\b -> "[ " <> toFilePath lfile <> " ] " <> b)
            $ bs
-        SPIB.fdWrite fileFd (bs <> "\n")
-

    swapRegs bs regs | length regs < size = regs ++ [bs]
                     | otherwise          = tail regs ++ [bs]
@@ -380,3 +385,27 @@ searchPath paths needle = go paths
    if p == toFilePath needle
      then isExecutable (basedir </> needle)
      else pure False
+
+
+findFiles :: Path Abs -> Regex -> IO [Path Rel]
+findFiles path regex = do
+  dirStream <- openDirStream (toFilePath path)
+  f         <-
+    (fmap . fmap) snd
+    . S.toList
+    . S.filter (\(_, p) -> match regex p)
+    $ dirContentsStream dirStream
+  pure $ join $ fmap parseRel f
+
+
+findFiles' :: Path Abs -> MP.Parsec Void Text () -> IO [Path Rel]
+findFiles' path parser = do
+  dirStream <- openDirStream (toFilePath path)
+  f         <-
+    (fmap . fmap) snd
+    . S.toList
+    . S.filter (\(_, p) -> case E.decodeUtf8' p of
+                             Left _ -> False
+                             Right p' -> isJust $ MP.parseMaybe parser p')
+    $ dirContentsStream dirStream
+  pure $ join $ fmap parseRel f
--- a/lib/GHCup/Utils/MegaParsec.hs
+++ b/lib/GHCup/Utils/MegaParsec.hs
@@ -0,0 +1,87 @@
+{-# LANGUAGE CPP                  #-}
+{-# LANGUAGE OverloadedStrings    #-}
+
+module GHCup.Utils.MegaParsec where
+
+import           GHCup.Types
+
+import           Control.Applicative
+import           Control.Monad
+#if !MIN_VERSION_base(4,13,0)
+import           Control.Monad.Fail             ( MonadFail )
+#endif
+import           Data.Functor
+import           Data.Maybe
+import           Data.Text                      ( Text )
+import           Data.Versions
+import           Data.Void
+
+import qualified Data.Text                     as T
+import qualified Text.Megaparsec               as MP
+
+
+choice' :: (MonadFail f, MP.MonadParsec e s f) => [f a] -> f a
+choice' []       = fail "Empty list"
+choice' [x     ] = x
+choice' (x : xs) = MP.try x <|> choice' xs
+
+
+parseUntil :: MP.Parsec Void Text a -> MP.Parsec Void Text Text
+parseUntil p = do
+  (MP.try (MP.lookAhead p) $> mempty)
+    <|> (do
+          c  <- T.singleton <$> MP.anySingle
+          c2 <- parseUntil p
+          pure (c `mappend` c2)
+        )
+
+parseUntil1 :: MP.Parsec Void Text a -> MP.Parsec Void Text Text
+parseUntil1 p = do
+  i1 <- MP.getOffset
+  t <- parseUntil p
+  i2 <- MP.getOffset
+  if i1 == i2 then fail "empty parse" else pure t
+
+
+
+-- | Parses e.g.
+--   * armv7-unknown-linux-gnueabihf-ghc
+--   * armv7-unknown-linux-gnueabihf-ghci
+ghcTargetBinP :: Text -> MP.Parsec Void Text (Maybe Text, Text)
+ghcTargetBinP t =
+  (,)
+    <$> (   MP.try
+            (Just <$> (parseUntil1 (MP.chunk "-" *> MP.chunk t)) <* MP.chunk "-"
+            )
+        <|> (flip const Nothing <$> mempty)
+        )
+    <*> (MP.chunk t <* MP.eof)
+
+
+-- | Extracts target triple and version from e.g.
+--   * armv7-unknown-linux-gnueabihf-8.8.3
+--   * armv7-unknown-linux-gnueabihf-8.8.3
+ghcTargetVerP :: MP.Parsec Void Text GHCTargetVersion
+ghcTargetVerP =
+  (\x y -> GHCTargetVersion x y)
+    <$> (MP.try (Just <$> (parseUntil1 (MP.chunk "-" *> verP)) <* MP.chunk "-")
+        <|> (flip const Nothing <$> mempty)
+        )
+    <*> (version' <* MP.eof)
+ where
+  verP :: MP.Parsec Void Text Text
+  verP = do
+    v <- version'
+    let startsWithDigists =
+          and
+            . take 3
+            . join
+            . (fmap . fmap)
+                (\case
+                  (Digits _) -> True
+                  (Str    _) -> False
+                )
+            $ (_vChunks v)
+    if startsWithDigists && not (isJust (_vEpoch v))
+      then pure $ prettyVer v
+      else fail "Oh"
--- a/lib/GHCup/Utils/Prelude.hs
+++ b/lib/GHCup/Utils/Prelude.hs
@@ -218,6 +218,12 @@ throwEither a = case a of
  Right r -> pure r


+throwEither' :: (Exception a, MonadThrow m) => a -> Either x b -> m b
+throwEither' e eth = case eth of
+  Left  _ -> throwM e
+  Right r -> pure r
+
+
 verToBS :: Version -> ByteString
 verToBS = E.encodeUtf8 . prettyVer

--- a/lib/GHCup/Version.hs
+++ b/lib/GHCup/Version.hs
@@ -13,7 +13,7 @@ import qualified Data.Text                     as T

 -- | This reflects the API version of the JSON.
 ghcupURL :: URI
-ghcupURL = [uri|https://www.haskell.org/ghcup/data/ghcup-0.0.1.json|]
+ghcupURL = [uri|https://www.haskell.org/ghcup/data/ghcup-0.0.2.json|]

 ghcUpVer :: PVP
 ghcUpVer = [pver|0.1.4|]
--- a/shell-completions/bash
+++ b/shell-completions/bash
@@ -0,0 +1,14 @@
+_ghcup()
+{
+    local CMDLINE
+    local IFS=$'\n'
+    CMDLINE=(--bash-completion-index $COMP_CWORD)
+
+    for arg in ${COMP_WORDS[@]}; do
+        CMDLINE=(${CMDLINE[@]} --bash-completion-word $arg)
+    done
+
+    COMPREPLY=( $(ghcup "${CMDLINE[@]}") )
+}
+
+complete -o filenames -F _ghcup ghcup
--- a/shell-completions/fish
+++ b/shell-completions/fish
@@ -0,0 +1,19 @@
+ function _ghcup
+    set -l cl (commandline --tokenize --current-process)
+    # Hack around fish issue #3934
+    set -l cn (commandline --tokenize --cut-at-cursor --current-process)
+    set -l cn (count $cn)
+    set -l tmpline --bash-completion-enriched --bash-completion-index $cn
+    for arg in $cl
+      set tmpline $tmpline --bash-completion-word $arg
+    end
+    for opt in (ghcup $tmpline)
+      if test -d $opt
+        echo -E "$opt/"
+      else
+        echo -E "$opt"
+      end
+    end
+end
+
+complete --no-files --command ghcup --arguments '(_ghcup)'
--- a/shell-completions/zsh
+++ b/shell-completions/zsh
@@ -0,0 +1,32 @@
+#compdef ghcup
+
+local request
+local completions
+local word
+local index=$((CURRENT - 1))
+
+request=(--bash-completion-enriched --bash-completion-index $index)
+for arg in ${words[@]}; do
+  request=(${request[@]} --bash-completion-word $arg)
+done
+
+IFS=$'\n' completions=($( ghcup "${request[@]}" ))
+
+for word in $completions; do
+  local -a parts
+
+  # Split the line at a tab if there is one.
+  IFS=$'\t' parts=($( echo $word ))
+
+  if [[ -n $parts[2] ]]; then
+     if [[ $word[1] == "-" ]]; then
+       local desc=("$parts[1] ($parts[2])")
+       compadd -d desc -- $parts[1]
+     else
+       local desc=($(print -f  "%-019s -- %s" $parts[1] $parts[2]))
+       compadd -l -d desc -- $parts[1]
+     fi
+  else
+    compadd -f -- $word
+  fi
+done
Author	SHA1	Message	Date
Julian Ospald	f46700e1cc	First cross try	2020-04-29 20:19:01 +02:00
Julian Ospald	d7a6935a1a	Fix CI on FreeBSD	2020-04-29 20:14:38 +02:00
Julian Ospald	a1282b2854	Fix missing import	2020-04-29 19:36:16 +02:00
Julian Ospald	34b9ea7d20	Fix CI	2020-04-29 19:17:59 +02:00
Julian Ospald	0ff7ebb1fd	Allow to set downloader	2020-04-29 19:12:58 +02:00
Julian Ospald	f83dcbc430	Run 'git describe' in CI to make sure --version reports it	2020-04-29 12:38:57 +02:00
Julian Ospald	56e4a6b15f	Invert curl flag to internal-downloader	2020-04-29 09:56:26 +02:00
Julian Ospald	ee9b2ec30d	Update docs	2020-04-28 17:41:08 +02:00
Julian Ospald	640cf1e2c1	Add zsh and fish completion wrt #19	2020-04-27 23:36:13 +02:00
Julian Ospald	56c439d716	Fall back to cached ghcup-<..>.json	2020-04-27 23:23:34 +02:00
Julian Ospald	1ed6e49a81	Install git in CI	2020-04-27 21:55:35 +02:00
Julian Ospald	fad9f83e6a	Add CentoOS tool requirements	2020-04-27 21:52:44 +02:00
Julian Ospald	2e28b0d00f	Fix release builds	2020-04-27 21:23:46 +02:00
Julian Ospald	ed4ff15f96	Update bash-completion	2020-04-27 07:47:46 +02:00
Julian Ospald	1d623723a2	Fix bug with missing ~/.ghcup/ghc/ dir	2020-04-26 22:06:00 +02:00
Julian Ospald	931080244f	Fix bug in logging	2020-04-26 20:17:59 +02:00
Julian Ospald	27e2e7f848	Fix building of documentation	2020-04-26 11:55:47 +02:00
Julian Ospald	8b638c7ecb	Rm stray ghc version	2020-04-25 13:22:12 +02:00
Julian Ospald	acd370611f	Fix gitlab CI	2020-04-25 13:02:34 +02:00
Julian Ospald	e1b5a89cee	Add bash-completion	2020-04-22 21:45:33 +02:00
Julian Ospald	5edebd57d9	Move download info into library	2020-04-22 19:32:48 +02:00
Julian Ospald	bcaccaaf31	Implement --keep	2020-04-22 19:32:14 +02:00
Julian Ospald	818a5d2d85	Document environment variables	2020-04-22 16:14:10 +02:00
Julian Ospald	13acce07d4	Allow to install X.Y versions	2020-04-22 16:13:58 +02:00
Julian Ospald	4ed5e21b7f	Validate that all GHC versions have a base tag	2020-04-22 16:13:23 +02:00
Julian Ospald	86aab6bb59	Improve output formatting	2020-04-22 16:12:56 +02:00
Julian Ospald	7f5cb64b18	Re-add --format-raw to list subcommand	2020-04-22 13:03:46 +02:00
Julian Ospald	6c12eb16eb	Add base tag	2020-04-22 11:59:40 +02:00
Julian Ospald	e637f90fae	List stray tools	2020-04-21 23:37:48 +02:00
Julian Ospald	5b33c3f491	Update TODO	2020-04-19 22:49:19 +02:00
Julian Ospald	1842ed464f	Also build 32bit release artifact	2020-04-19 22:31:53 +02:00
Julian Ospald	296bbdd561	Fix digest of ghc-8.8.3-i386-unknown-linux-musl.tar.xz	2020-04-19 22:05:18 +02:00