Merge pull request #2 from cdepillabout/static-compilation

Make static compilation a little easier

Author: cdepillabout

CHANGELOG.md

@@ -1,4 +1,19 @@
 
+## next
+
+*   Add a `callPackage` argument to `stacklock2nix` so that users can easily statically-compile Haskell packages.
+
+    This could be used like the following:
+
+    ```nix
+    my-haskell-stacklock = final.stacklock2nix {
+      stackYaml = ./stack.yaml;
+      baseHaskellPkgSet = final.pkgsStatic.haskell.packages.ghc924;
+      callPackage = final.pkgsStatic.callPackage;
+      ...
+    };
+    ```
+
 ## 0.1.0
 
 *   Initial release.

README.md

@@ -170,6 +170,8 @@ Advantages of haskell.nix:
     (without also requiring a `stack.yaml.lock` file).
 -   A shared cache from IOHK.  (Although users commonly report not
     getting cache hits for various reasons.)
+-   The ability to cross-compile Haskell libraries.  (For instance,
+    building an ARM64 binary on an x86_64 machine.)
 
 Advantages of `stacklock2nix`:
 
@@ -205,3 +207,26 @@ PRs, and helping people who run into problems.  I prioritize issues and PRs
 from people who are sponsors.
 
 You can find the sponsor page [here](https://github.com/sponsors/cdepillabout).
+
+## FAQ
+
+-   **Is it possible to use `stacklock2nix` to build a statically-linked Haskell library?**
+
+    Recent versions (since mid-2022) of the Haskell infrastructure in Nixpkgs
+    have the ability to link Haskell executables completely statically.  An
+    easy way to test this out is to use the
+    [`pkgsStatic` subpackage set](https://functor.tokyo/blog/2021-10-20-nix-cross-static)
+    in Nixpkgs.
+
+    Instead of passing a value like `pkgs.haskell.packages.ghc924` to the
+    `baseHaskellPkgSet` of the `stacklock2nix` function, pass
+    `pkgs.pkgsStatic.haskell.packages.ghc924`:
+
+    ```nix
+    my-haskell-stacklock = final.stacklock2nix {
+      stackYaml = ./stack.yaml;
+      baseHaskellPkgSet = final.pkgsStatic.haskell.packages.ghc924;
+      callPackage = final.pkgsStatic.callPackage;
+      ...
+    };
+    ```

nix/build-support/stacklock2nix/default.nix

@@ -3,10 +3,9 @@
 , fetchurl
 , haskell
 , lib
-, pkgs
 , runCommand
 , stdenv
-}:
+}@topargs:
 
 { # The path to your stack.yaml file.
   #
@@ -77,6 +76,7 @@
   #
   # This is not used if `baseHaskellPkgSet` is `null`.
   all-cabal-hashes ? null
+, callPackage ? topargs.callPackage
 }:
 
 # The stack.yaml path can be computed from the stack.yaml.lock path, or