From 539cff1b682349537e40964a2b9aeb94ff266c94 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Madeleine=20Sydney=20=C5=9Alaga?= <msyds@deertopia.net>
Date: Fri, 1 May 2026 15:04:27 -0600
Subject: [PATCH] feat(haskell): ghc-with-packages

---
 modules/home/haskell.nix                  | 31 +++++++++++
 modules/home/haskell/ghc-with-packages.sh | 52 ++++++++++++++++++
 modules/home/users/crumb/haskell.nix      | 67 -----------------------
 users/msyds/default.nix                   |  1 +
 4 files changed, 84 insertions(+), 67 deletions(-)
 create mode 100644 modules/home/haskell.nix
 create mode 100644 modules/home/haskell/ghc-with-packages.sh
 delete mode 100644 modules/home/users/crumb/haskell.nix

diff --git a/modules/home/haskell.nix b/modules/home/haskell.nix
new file mode 100644
index 0000000..9b9fc26
--- /dev/null
+++ b/modules/home/haskell.nix
@@ -0,0 +1,31 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.sydnix.haskell;
+in {
+  options.sydnix.haskell.enable =
+    lib.mkEnableOption "Haskell";
+
+  config = lib.mkIf cfg.enable {
+    # Convenient shorthand for quickly opening Haskell REPLs.
+    programs.bash.profileExtra =
+      builtins.readFile ./haskell/ghc-with-packages.sh;
+
+    home.file.".ghc/ghci.conf".text = ''
+      :set prompt "\x1b[38;5;5mλ>\x1b[0m "
+      :set prompt-cont "\x1b[38;5;5m|>\x1b[0m "
+    '';
+
+    sydnix.impermanence.cache.directories =
+      let xdg-cache-dir =
+            config.home.cacheHome
+              or "${config.home.homeDirectory}/.cache";
+      in [
+        # We don't want to rebuild Hackage simply due to a reboot, do we?  }:)
+        (lib.removePrefix "${config.home.homeDirectory}/"
+          "${xdg-cache-dir}/cabal")
+        ".stack"
+      ];
+  };
+}
+
diff --git a/modules/home/haskell/ghc-with-packages.sh b/modules/home/haskell/ghc-with-packages.sh
new file mode 100644
index 0000000..66505bc
--- /dev/null
+++ b/modules/home/haskell/ghc-with-packages.sh
@@ -0,0 +1,52 @@
+declare -a default_ghc_packages=(pretty-simple lens)
+
+ghc-with-packages () {
+  declare -a packages=()
+  local GHC_COMMAND=${GHC_COMMAND:-"ghc"}
+  packages+=$default_ghc_packages
+  local exit=0 stop_args
+  while [[ ! -z "$1" && -z "$stop_args" ]]; do
+      local opt="$1"
+      shift 1
+    case "$opt" in
+        "--")
+            stop_args=1
+            ;;
+        "-p")
+            while [[ ! -z "$1" && "$1" != -* ]]; do
+                packages+=("$1")
+                shift 1
+            done
+            ;;
+      *|"-h")
+        exit=1
+        ;;
+    esac
+  done
+
+  local pretty_simple
+
+  for p in "$packages"; do
+      if [[ "$p" = "pretty-simple" ]]; then
+          pretty_simple="-interactive-print=Text.Pretty.Simple.pPrint"
+      fi
+  done
+
+  if [[ "$exit" -eq 0 ]]; then
+      # echo "packages: ${packages[@]}"
+      # echo "args: $*"
+      local pkgs="${packages[@]}"
+      nix-shell \
+          -p "haskellPackages.ghcWithPackages (p: with p; [ $pkgs ])" \
+          --run "$GHC_COMMAND $pretty_simple $*"
+  else
+      echo >&2 "Usage: ghci-with-packages [-p packages…] [-- ghci-options]"
+      return $exit
+  fi
+}
+export -f ghc-with-packages
+
+ghci-with-packages () {
+    GHC_COMMAND=ghci ghc-with-packages "$@"
+}
+export -f ghci-with-packages
diff --git a/modules/home/users/crumb/haskell.nix b/modules/home/users/crumb/haskell.nix
deleted file mode 100644
index aa11777..0000000
--- a/modules/home/users/crumb/haskell.nix
+++ /dev/null
@@ -1,67 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-let
-  cfg = config.sydnix.users.crumb.haskell;
-in {
-  options.sydnix.users.crumb.haskell.enable =
-    lib.mkEnableOption "Haskell, à la crumb";
-
-  config = lib.mkIf cfg.enable {
-    # Convenient shorthand for quickly opening Haskell REPLs.
-    programs.bash.profileExtra = ''
-      # Start a GHCi REPL with the given packages made available.
-      ghci-with-packages () {
-        packages=""
-        while getopts 'p:h' opt; do
-          case "$opt" in
-            p)
-              packages="''${OPTARG}"
-              ;;
-            ?|h)
-              echo >&2 "Usage: $(basename $0) [-p packages] [-- ghci-options]"
-              exit 1
-              ;;
-          esac
-        done
-        shift "$(($OPTIND -1))"
-
-        nix-shell -p "haskellPackages.ghcWithPackages (p: with p; [ $packages ])" \
-          --run "ghci $@"
-      }
-      export -f ghci-with-packages
-
-      # Run GHC with the given packages made available.
-      ghc-with-packages () {
-        packages=""
-        while getopts 'p:h' opt; do
-          case "$opt" in
-            p)
-              packages="''${OPTARG}"
-              ;;
-            ?|h)
-              echo >&2 "Usage: $(basename $0) [-p packages] [-- ghc-options]"
-              exit 1
-              ;;
-          esac
-        done
-        shift "$(($OPTIND -1))"
-
-        nix-shell -p "haskellPackages.ghcWithPackages (p: with p; [ $packages ])" \
-          --run "ghc $@"
-      }
-      export -f ghc-with-packages
-    '';
-
-    sydnix.impermanence.cache.directories =
-      let xdg-cache-dir =
-            config.home.cacheHome
-              or "${config.home.homeDirectory}/.cache";
-      in [
-        # We don't want to rebuild Hackage simply due to a reboot, do we?  }:)
-        (lib.removePrefix "${config.home.homeDirectory}/"
-          "${xdg-cache-dir}/cabal")
-        ".stack"
-      ];
-  };
-}
-
diff --git a/users/msyds/default.nix b/users/msyds/default.nix
index 6756c35..bdd6695 100644
--- a/users/msyds/default.nix
+++ b/users/msyds/default.nix
@@ -51,6 +51,7 @@
         drawing-tablet.enable = on "sydpc";
         easyeffects.enable = on "sydpc";
         ryujinx.enable = on "sydpc";
+        haskell.enable = true;
         sops = {
           enable = true;
           keyFile = "/persist/private-keys/age/crumb";