在nix上haskell开发环境中使用hoogle

Question

我试图在Haskell开发环境中使用hoogle，就像奥查尔斯维基描述的那样

我已经像下面这样修改了shell.nix，以便使用hoogleLocal，但是它似乎没有为我安装hoogle二进制文件。

let
  pkgs = import <nixpkgs> {};

  # I'm attempting to use hoogle here, but it is not working.
  haskellPackages =
    let callPackage = pkgs.lib.callPackageWith haskellPackages;
    in pkgs.recurseIntoAttrs (pkgs.haskellPackages.override {
      extension = self: super: {
        thiscurrentpackage = self.callPackage ./. {};
        hoogleLocal = pkgs.haskellPackages.hoogleLocal.override {
          packages = self.thiscurrentpackage;
        };
      };
    });
in pkgs.myEnvFun {
  name = haskellPackages.thiscurrentpackage.name;
  buildInputs = [
    (haskellPackages.ghcWithPackages (hs: ([
      hs.cabalInstall
      hs.ghcMod
      hs.yesodBin
      # This doesn't appear to install the hoogle binary?
      hs.hoogleLocal
    ] ++ hs.thiscurrentpackage.propagatedNativeBuildInputs)))
  ];
}

在生成的shell中，hoogle二进制文件不可用。

如果我将hs.hoogle包含到buildInputs中，则会安装hoogle二进制文件，但它无法找到数据库。下面是当我尝试使用它时会发生的事情。

$ nix-shell
......
$ hoogle Monad
Could not find some databases: default
Searching in:
  .
    /nix/store/91y9q2y5a2ws8xgcsx1gkhfagc0f2qz6-haskell-hoogle-ghc7.8.3-4.2.36-shared/share/x86_64-linux-ghc-7.8.3/hoogle-4.2.36/databases

    There are no available databases, generate them with: hoogle data
$ hoogle data
    hoogle: /nix/store/91y9q2y5a2ws8xgcsx1gkhfagc0f2qz6-haskell-hoogle-ghc7.8.3-4.2.36-shared/share/x86_64-linux-ghc-7.8.3/hoogle-4.2.36/databases:
changeWorkingDirectory: does not exist (No such file or directory)
$

对于O‘’Charles所描述的设置，我如何使它正确工作？

编辑：原始shell.nix与这个答案中的相同。

Answer 1

使用@Ben的答案作为参考，以下是我需要对cabal2nix --shell文件进行的必要更改的不同之处：

diff --git a/shell.nix b/shell.nix
index 540ade3..e207d6e 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,4 +1,4 @@
-{ nixpkgs ? import <nixpkgs> {}, compiler ? "default", doBenchmark ? false }:
+{ nixpkgs ? import <nixpkgs> {}, compiler ? "default", doBenchmark ? false , withHoogle ? true}:

 let

@@ -21,10 +21,23 @@ let
         license = stdenv.lib.licenses.bsd3;
       };

-  haskellPackages = if compiler == "default"
+  haskellPackages' = if compiler == "default"
                        then pkgs.haskellPackages
                        else pkgs.haskell.packages.${compiler};

+  haskellPackages = (
+    if withHoogle
+    then  haskellPackages'.override {
+      overrides = (self: super:
+        {
+          ghc = super.ghc // { withPackages = super.ghc.withHoogle; };
+          ghcWithPackages = self.ghc.withPackages;
+        }
+      );
+    }
+    else haskellPackages'
+  );
+
   variant = if doBenchmark then pkgs.haskell.lib.doBenchmark else pkgs.lib.id;

   drv = variant (haskellPackages.callPackage f {});```