direnv: add poetry layout for direnv

modules/programs/direnv.nix

@@ -15,6 +15,24 @@ in
     home-manager.users.moritz.programs.direnv = {
       enable = true;
       nix-direnv.enable = true;
+      stdlib = ''
+         layout_poetry() {
+          if [[ ! -f pyproject.toml ]]; then
+            log_error 'No pyproject.toml found. Use `poetry new` or `poetry init` to create one first.'
+            exit 2
+          fi
+
+          local VENV=$(poetry env info --path)
+          if [[ -z $VENV || ! -d $VENV/bin ]]; then
+            log_error 'No poetry virtual environment found. Use `poetry install` to create one first.'
+            exit 2
+          fi
+
+          export VIRTUAL_ENV=$VENV
+          export POETRY_ACTIVE=1
+          PATH_add "$VENV/bin"
+        }
+      '';
     };
   };
 }