refactor(flake): move some code out of flake.in.nix

packages/repl/default.nix

@@ -0,0 +1,26 @@
+# modified from https://github.com/fufexan/dotfiles/blob/main/pkgs/repl/default.nix
+{
+  coreutils,
+  gnused,
+  writeShellScriptBin,
+  ...
+}: let
+  repl = ./repl.nix;
+  example = command: desc: ''\n\u001b[33m ${command}\u001b[0m - ${desc}'';
+in
+  writeShellScriptBin "repl" ''
+    case "$1" in
+      "-h"|"--help"|"help")
+        printf "%b\n\e[4mUsage\e[0m: \
+          ${example "repl" "Loads system flake if available."} \
+          ${example "repl /path/to/flake.nix" "Loads specified flake."}\n"
+      ;;
+      *)
+        if [ -z "$1" ]; then
+          nix repl --arg flakePath $(${coreutils}/bin/readlink -f "$FLAKE") --file ${repl}
+        else
+          nix repl --arg flakePath $(${coreutils}/bin/readlink -f $1 | ${gnused}/bin/sed 's|/flake.nix||') --file ${repl}
+        fi
+      ;;
+    esac
+  ''