✨ Create Command class (#4)

* ✨ Create Command class

* ✨ Create Command class

docs/source/conf.py

@@ -34,6 +34,7 @@ release = '6.0.0a12'
 extensions = [
     "sphinx.ext.autodoc",
     "sphinx.ext.intersphinx",
+    'sphinx.ext.todo',
 ]
 
 # Add any paths that contain templates here, relative to this directory.
@@ -91,3 +92,7 @@ autodoc_default_options = {
     'special-members': '__init__',
     'undoc-members': True,
 }
+
+# -- Automodule settings -----------------------------------------------------
+
+todo_include_todos = True

docs/source/index.rst

@@ -25,3 +25,8 @@ Indices and tables
 * :ref:`genindex`
 * :ref:`modindex`
 * :ref:`search`
+
+To do
+-----
+
+.. todolist::

royalnet/engineer/command.py

@@ -0,0 +1,77 @@
+"""
+Commands are used to quickly create single-message conversations
+"""
+
+from __future__ import annotations
+import royalnet.royaltyping as t
+
+import logging
+import functools
+import re
+
+from . import bullet
+from . import teleporter
+
+log = logging.getLogger(__name__)
+
+
+class Command:
+    """
+    A decorator to create a command that can be called from the chat by entering a certain :attr:`.pattern` of
+    characters:
+
+    .. code-block:: text
+
+        /echo Hello!
+        # Hello!
+
+    """
+
+    def __init__(self,
+                 prefix: str,
+                 name: str,
+                 syntax: str,
+                 *,
+                 pattern: str = r"^{prefix}{name} {syntax}",
+                 doc: str = ""):
+        self.prefix: str = prefix
+        """
+        The prefix used in the command (usually ``/`` or ``!``).
+        """
+
+        self.name: str = name
+        """
+        The name of the command, usually all lowercase.
+        """
+
+        self.syntax: str = syntax
+        """
+        A regex describing the syntax of the command, using named capture groups ``(?P<name>...)`` to capture arguments
+        that should be passed to the function.
+        """
+
+        self.pattern: re.Pattern = re.compile(pattern.format(prefix=prefix, name=name, syntax=syntax))
+        """
+        The compiled regex pattern. 
+        
+        By default, it :meth:`str.format` the passed string with the ``prefix``, ``name`` and ``syntax`` keyword 
+        arguments, but this behaviour can be changed by passing a different ``pattern`` to :meth:`__init__`.
+        """
+
+        self.doc: str = doc
+        """
+        A string explaining how this command should be used. Useful for command lists or help commands.
+        """
+
+    def __call__(self, f):
+        """
+        The decorator interface of the command.
+        """
+        @functools.wraps(f)
+        async def decorated(_msg: bullet.Message, **original_kwargs) -> t.Conversation:
+            text: str = await _msg.text()
+            match: re.Match = self.pattern.search(text)
+            match_kwargs: dict = match.groupdict()
+            teleported: t.Callable = teleporter.teleporter(is_async=True, validate_output=False)(f)
+            return await teleported(_msg=_msg, **original_kwargs, **match_kwargs)
+        return decorated