Experiment with a decorator based API

docs/source/index.rst

@@ -302,7 +302,8 @@ Control application complexity by namespacing UI and server code.
     :toctree: reference/
     :template: class.rst
 
-    Module
+    module_ui
+    module_server
 
 
 Type hints

examples/moduleapp/app.py

@@ -3,6 +3,7 @@
 # ============================================================
 # Counter module
 # ============================================================
+@module_ui
 def counter_ui(label: str = "Increment counter") -> ui.TagChildArg:
     return ui.div(
         {"style": "border: 1px solid #ccc; border-radius: 5px; margin: 5px 0;"},
@@ -12,7 +13,8 @@ def counter_ui(label: str = "Increment counter") -> ui.TagChildArg:
     )
 
 
-def counter_server(input: Inputs, output: Outputs, session: Session):
+@module_server
+def counter_server(input: Inputs, output: Outputs, session: Session) -> int:
     count: reactive.Value[int] = reactive.Value(0)
 
     @reactive.Effect()
@@ -25,22 +27,22 @@ def _():
     def out() -> str:
         return f"Click count is {count()}"
 
-
-counter_module = Module(counter_ui, counter_server)
+    return 1
 
 
 # =============================================================================
 # App that uses module
 # =============================================================================
 app_ui = ui.page_fluid(
-    counter_module.ui("counter1", "Counter 1"),
-    counter_module.ui("counter2", "Counter 2"),
+    counter_ui("counter1", "Counter 1"),
+    counter_ui("counter2", "Counter 2"),
 )
 
 
 def server(input: Inputs, output: Outputs, session: Session):
-    counter_module.server("counter1")
-    counter_module.server("counter2")
+    counter_server("counter1")
+    val = counter_server("counter2")
+    print(val)
 
 
 app = App(app_ui, server)

shiny/__init__.py

@@ -13,7 +13,7 @@
 # Private submodules that have some user-facing functionality
 from ._app import App
 from ._decorators import event
-from ._modules import Module
+from ._modules import module_ui, module_server
 from ._validation import req
 
 if _is_pyodide:
@@ -42,7 +42,8 @@
     # _main.py
     "run_app",
     # _modules.py
-    "Module",
+    "module_ui",
+    "module_server",
     # _render.py
     "render_text",
     "render_plot",

shiny/_modules.py

@@ -1,6 +1,6 @@
-__all__ = ("Module", "namespaced_id")
+__all__ = ("namespaced_id", "module_ui", "module_server")
 
-from typing import Any, Callable, Optional
+from typing import Any, Callable, Optional, TypeVar, ParamSpec, Concatenate
 
 from htmltools import TagChildArg
 
@@ -78,59 +78,83 @@ def __init__(self, ns: str):
         self._ns = ns
 
 
-@add_example()
-class Module:
-    """
-    Modularize UI and server-side logic.
-
-    Parameters
-    ----------
-    ui
-        The module's UI definition.
-    server
-        The module's server-side logic.
-    """
+P = ParamSpec("P")
+R = TypeVar("R")
+
 
-    def __init__(
-        self,
-        ui: Callable[..., TagChildArg],
-        server: Callable[[ModuleInputs, ModuleOutputs, ModuleSession], None],
-    ) -> None:
-        self._ui: Callable[..., TagChildArg] = ui
-        self._server: Callable[
-            [ModuleInputs, ModuleOutputs, ModuleSession], None
-        ] = server
-
-    def ui(self, ns: str, *args: Any) -> TagChildArg:
-        """
-        Render the module's UI.
-
-        Parameters
-        ----------
-        namespace
-            A namespace for the module.
-        args
-            Additional arguments to pass to the module's UI definition.
-        """
-
-        # Create a fake session so that namespaced_id() knows
-        # what the relevant namespace is
+def module_ui(fn: Callable[P, R]) -> Callable[Concatenate[str, P], R]:
+    def wrapper(ns: str, *args: P.args, **kwargs: P.kwargs) -> R:
         with session_context(MockModuleSession(ns)):
-            return self._ui(*args)
-
-    def server(self, ns: str, *, session: Optional[Session] = None) -> None:
-        """
-        Invoke the module's server-side logic.
-
-        Parameters
-        ----------
-        ns
-            A namespace for the module.
-        session
-            A :class:`~shiny.Session` instance. If not provided, it is inferred via
-            :func:`~shiny.session.get_current_session`.
-        """
-
-        mod_sess = ModuleSession(ns, require_active_session(session))
+            return fn(*args, **kwargs)
+
+    return wrapper
+
+
+def module_server(
+    fn: Callable[Concatenate[Inputs, Outputs, Session, P], R]
+) -> Callable[Concatenate[str, P], R]:
+    def wrapper(ns: str, *args: P.args, **kwargs: P.kwargs) -> R:
+        mod_sess = ModuleSession(ns, require_active_session(None))
         with session_context(mod_sess):
-            return self._server(mod_sess.input, mod_sess.output, mod_sess)
+            return fn(mod_sess.input, mod_sess.output, mod_sess, *args, **kwargs)
+
+    return wrapper
+
+
+# @add_example()
+# class Module:
+#    """
+#    Modularize UI and server-side logic.
+#
+#    Parameters
+#    ----------
+#    ui
+#        The module's UI definition.
+#    server
+#        The module's server-side logic.
+#    """
+#
+#    def __init__(
+#        self,
+#        ui: Callable[..., TagChildArg],
+#        server: Callable[[ModuleInputs, ModuleOutputs, ModuleSession], None],
+#    ) -> None:
+#        self._ui: Callable[..., TagChildArg] = ui
+#        self._server: Callable[
+#            [ModuleInputs, ModuleOutputs, ModuleSession], None
+#        ] = server
+#
+#    def ui(self, ns: str, *args: Any) -> TagChildArg:
+#        """
+#        Render the module's UI.
+#
+#        Parameters
+#        ----------
+#        namespace
+#            A namespace for the module.
+#        args
+#            Additional arguments to pass to the module's UI definition.
+#        """
+#
+#        # Create a fake session so that namespaced_id() knows
+#        # what the relevant namespace is
+#        with session_context(MockModuleSession(ns)):
+#            return self._ui(*args)
+#
+#    def server(self, ns: str, *, session: Optional[Session] = None) -> None:
+#        """
+#        Invoke the module's server-side logic.
+#
+#        Parameters
+#        ----------
+#        ns
+#            A namespace for the module.
+#        session
+#            A :class:`~shiny.Session` instance. If not provided, it is inferred via
+#            :func:`~shiny.session.get_current_session`.
+#        """
+#
+#        mod_sess = ModuleSession(ns, require_active_session(session))
+#        with session_context(mod_sess):
+#            return self._server(mod_sess.input, mod_sess.output, mod_sess)
+#