Add mkDerivation that is compatible with agda2hs

Author: HeinrichApfelmus

nix/agda2hs.nix

@@ -1,7 +1,19 @@
-# this file should be very close to a copy of nixpkgs/pkgs/build-support/agda/default.nix
-# I think I took the version from https://github.com/NixOS/nixpkgs/blob/bbe6402ecacfc3a0e2c65e3527c2cbe148b98ff8/pkgs/build-support/agda/default.nix
+# This file should be very close to a copy of nixpkgs/pkgs/build-support/agda/default.nix
+# The present file appears to be an amalgaman of
+#   https://github.com/NixOS/nixpkgs/blob/bbe6402ecacfc3a0e2c65e3527c2cbe148b98ff8/pkgs/build-support/agda/default.nix
+#   https://github.com/NixOS/nixpkgs/blob/583eef75e722741878b186f5bdf5a826d638f868/pkgs/build-support/agda/default.nix
 # but it would be nice to expose this in upstream so that we don't have to duplicate the file
-{stdenv, lib, self, agda2hs, runCommandNoCC, makeWrapper, writeText, mkShell, ghcWithPackages}:
+{
+  stdenv,
+  lib,
+  self,
+  agda2hs,
+  runCommandNoCC,
+  makeWrapper,
+  writeText,
+  ghcWithPackages,
+}:
+
 with lib.strings;
 let
   withPackages' = {
@@ -26,7 +38,81 @@ let
       --add-flags "--local-interfaces"
     ''; # Local interfaces has been added for now: See https://github.com/agda/agda/issues/4526
   withPackages = arg: if builtins.isAttrs arg then withPackages' arg else withPackages' { pkgs = arg; };
+
+  extensions = [
+    "agda"
+    "agda-lib"
+    "agdai"
+    "lagda"
+    "lagda.md"
+    "lagda.org"
+    "lagda.rst"
+    "lagda.tex"
+    "lagda.typ"
+  ];
+
+  defaults =
+    {
+      pname,
+      meta,
+      buildInputs ? [ ],
+      everythingFile ? "./Everything.agda",
+      includePaths ? [ ],
+      libraryName ? pname,
+      libraryFile ? "${libraryName}.agda-lib",
+      buildPhase ? null,
+      installPhase ? null,
+      extraExtensions ? [ ],
+      ...
+    }:
+    let
+      agdaWithArgs = withPackages (filter (p: p ? isAgdaDerivation) buildInputs);
+      includePathArgs = concatMapStrings (path: "-i" + path + " ") (
+        includePaths ++ [ (dirOf everythingFile) ]
+      );
+    in
+    {
+      inherit libraryName libraryFile;
+
+      isAgdaDerivation = true;
+
+      buildInputs = buildInputs ++ [ agdaWithArgs ];
+
+      buildPhase =
+        if buildPhase != null then
+          buildPhase
+        else
+          ''
+            runHook preBuild
+            agda2hs ${includePathArgs} ${everythingFile}
+            rm ${everythingFile} ${everythingFile}i
+            runHook postBuild
+          '';
+
+      installPhase =
+        if installPhase != null then
+          installPhase
+        else
+          ''
+            runHook preInstall
+            mkdir -p $out
+            find \( ${
+              concatMapStringsSep " -or " (p: "-name '*.${p}'") (extensions ++ extraExtensions)
+            } \) -exec cp -p --parents -t "$out" {} +
+            runHook postInstall
+          '';
+
+      # As documented at https://github.com/NixOS/nixpkgs/issues/172752,
+      # we need to set LC_ALL to an UTF-8-supporting locale. However, on
+      # darwin, it seems that there is no standard such locale; luckily,
+      # the referenced issue doesn't seem to surface on darwin. Hence let's
+      # set this only on non-darwin.
+      LC_ALL = optionalString (!stdenv.hostPlatform.isDarwin) "C.UTF-8";
+    };
+
 in {
+  mkDerivation = args: stdenv.mkDerivation (args // defaults args);
+
   inherit withPackages;
   agda2hs = withPackages [];
 }

nix/default.nix

@@ -6,7 +6,7 @@ let
   lib = import ./lib.nix { inherit pkgs; };
   version = "1.3";
 
-  base-lib = pkgs.agdaPackages.mkDerivation {
+  base-lib = lib.mkDerivation {
     pname = "base";
     meta = { };
     version = "4.18";

nix/lib.nix

@@ -25,5 +25,5 @@ in
   agda2hs-pkg = hsrc;
   agda2hs-hs = hpkg;
   agda2hs-expr = expr;
-  inherit (agda2hs) agda2hs withPackages;
+  inherit (agda2hs) agda2hs withPackages mkDerivation;
 }