From fde80955397d31c7bbbcf0f76126f8b4515ae97b Mon Sep 17 00:00:00 2001
From: Xavier Dectot <xavier@wheredoibegin.fr>
Date: Tue, 15 Apr 2025 12:11:08 +0200
Subject: [PATCH] b

---
 JuicyPixels-blurhash.cabal                   | 13 +++++++--
 Setup.hs                                     | 18 ++++++++++++
 doctest/Main.hs                              | 29 ++++++++++++++++++--
 src/Codec/Picture/Blurhash/Internal/DList.hs |  2 +-
 4 files changed, 57 insertions(+), 5 deletions(-)

diff --git a/JuicyPixels-blurhash.cabal b/JuicyPixels-blurhash.cabal
index 587f149..0379ad0 100644
--- a/JuicyPixels-blurhash.cabal
+++ b/JuicyPixels-blurhash.cabal
@@ -19,7 +19,7 @@ maintainer:     sam.protas@gmail.com
 copyright:      2020 Sam Protas
 license:        BSD3
 license-file:   LICENSE
-build-type:     Simple
+build-type:     Custom
 extra-source-files:
     README.md
     ChangeLog.md
@@ -34,6 +34,12 @@ source-repository head
   type: git
   location: https://github.com/SamProtas/JuicyPixels-blurhash
 
+custom-setup
+  setup-depends:
+      base
+    , Cabal
+    , cabal-doctest
+
 library
   exposed-modules:
       Codec.Picture.Blurhash
@@ -80,7 +86,7 @@ executable JuicyPixels-blurhash-exe
     , vector >=0.10 && <0.13
   default-language: Haskell2010
 
-test-suite JuicyPixels-blurhash-doctests
+test-suite doctests
   type: exitcode-stdio-1.0
   main-is: Main.hs
   other-modules:
@@ -98,6 +104,9 @@ test-suite JuicyPixels-blurhash-doctests
     , doctest >=0.16.2 && <0.20
     , filepath >=1.4.1.1 && <1.5
     , vector >=0.10 && <0.13
+    , directory
+    , base-compat
+    , cabal-doctest >= 1.0.0
   default-language: Haskell2010
 
 test-suite JuicyPixels-blurhash-test
diff --git a/Setup.hs b/Setup.hs
index 9a994af..ec0be70 100644
--- a/Setup.hs
+++ b/Setup.hs
@@ -1,2 +1,20 @@
+{-# LANGUAGE CPP #-}
+
+module Main
+  ( main
+  ) where
+#ifndef MIN_VERSION_cabal_doctest
+#define MIN_VERSION_cabal_doctest(x,y,z) 0
+#endif
+
+#if MIN_VERSION_cabal_doctest(1,0,0)
+import Distribution.Extra.Doctest (defaultMainWithDoctests)
+
+main :: IO ()
+main = defaultMainWithDoctests "doctests"
+#else
 import Distribution.Simple
+
+main :: IO ()
 main = defaultMain
+#endif
diff --git a/doctest/Main.hs b/doctest/Main.hs
index cfccc9b..f793db0 100644
--- a/doctest/Main.hs
+++ b/doctest/Main.hs
@@ -2,6 +2,31 @@ module Main where
 
 import System.FilePath.Glob (glob)
 import Test.DocTest (doctest)
-
+import GHC.IO.Encoding (setLocaleEncoding)
+import System.Directory (getCurrentDirectory, makeAbsolute)
+import System.FilePath.Posix ((</>))
+import System.IO (utf8)
+import Build_doctests (pkgs)
+ 
 main :: IO ()
-main = glob "src/**/*.hs" >>= doctest
+main = do
+  sourceFiles <- glob "src/**/*.hs"
+  let ghcExtensions =
+            [ "-XDerivingStrategies"
+            , "-XInstanceSigs"
+            , "-XScopedTypeVariables"
+            , "-XViewPatterns"
+            ]
+
+  setLocaleEncoding utf8
+  pwd    <- getCurrentDirectory
+  prefix <- makeAbsolute pwd
+  let customFlags =
+          [ "-package-env=-"
+          , "-hide-all-packages"
+          , "-no-user-package-db"
+          , "-package-db=" ++ prefix </> "dist/package.conf.inplace"
+          ]
+
+  doctest $ customFlags ++ pkgs ++ sourceFiles ++ ghcExtensions
+      
diff --git a/src/Codec/Picture/Blurhash/Internal/DList.hs b/src/Codec/Picture/Blurhash/Internal/DList.hs
index acd67f5..1148293 100644
--- a/src/Codec/Picture/Blurhash/Internal/DList.hs
+++ b/src/Codec/Picture/Blurhash/Internal/DList.hs
@@ -20,7 +20,7 @@ toDList l = \l' -> l ++ l'
 
 -- | Convert a difference list to a list
 dListToList :: DList a -> [a]
-dListToList = ($[])
+dListToList = ($ [])
 
 -- | Append an item to the end of a difference list
 dListSnoc :: DList a -> a -> DList a
-- 
2.49.0