chore: enable doctests (#181)

Author: NickSeagull

.github/workflows/test.yml

@@ -46,5 +46,8 @@ jobs:
       - name: Run core tests
         run: nix-shell --run "cabal test core"
 
+      - name: Run core doctests
+        run: nix-shell --run "run-doctests-verbose"
+
       - name: Run CLI tests
         run: nix-shell --run "cabal test cli"

core/core/Array.hs

@@ -94,7 +94,8 @@ unwrap (Array v) = v
 
 -- | Return an empty array.
 --
--- > length empty == 0
+-- >>> empty :: Array Int
+-- Array []
 empty :: Array a
 empty =
   Array Data.Vector.empty

shell.nix

@@ -22,6 +22,7 @@ in pkgs.mkShell rec {
     pkgs.hlint
     pkgs.haskellPackages.zlib
     pkgs.haskellPackages.hspec-discover
+    pkgs.haskellPackages.doctest
 
     # Nix dev tools
     pkgs.nil
@@ -36,6 +37,14 @@ in pkgs.mkShell rec {
   shellHook = ''
     unset TEMP TMP TEMPDIR TMPDIR   # Required for nix-shell to work
     ${pre-commit.pre-commit-check.shellHook}
+
+    run-doctests-verbose() {
+      cabal repl --with-compiler=doctest --repl-options=--verbose core
+    }
+    
+    run-doctests() {
+      cabal repl --with-compiler=doctest core
+    }
   '';
 
   # Required for cabal to find the location of zlib and other native libraries