Allow commands to be defined declaratively

awwparse/__init__.py

@@ -6,8 +6,11 @@
     :copyright: 2012 by Daniel Neuhäuser
     :license: BSD, see LICENSE.rst for details
 """
+from __future__ import absolute_import
 import sys
 import textwrap
+from types import MethodType
+from functools import partial
 from collections import deque
 
 from six import u
@@ -194,10 +197,18 @@ def __init__(self):
             force_list(self.__class__.arguments)
         )
         self.parent = None
+
         signature = Signature.from_method(self.main)
         if signature.annotations:
             self._populate_from_signature(self, signature)
 
+        for name in dir(self):
+            attribute = getattr(self, name)
+            if isinstance(attribute, Command):
+                if not isinstance(attribute.main, MethodType):
+                    attribute.main = partial(attribute.main, self)
+                self.add_command(name, attribute)
+
     @property
     def option_prefixes(self):
         """

awwparse/testsuite/init.py

@@ -186,6 +186,20 @@ def main(self, a: Integer(), b: Integer()):
         self.assert_equal(Foo().run(["1", "1"]), 2)
         """
 
+    def test_declarative(self):
+        results = []
+        class Foo(Command):
+            arguments = Argument(Integer(), "a")
+
+            def main(self, a):
+                results.append(a)
+
+        class Bar(Command):
+            foo = Foo()
+
+        Bar().run(["foo", "1"])
+        self.assert_equal(results, [1])
+
     def test_option_shorts_and_longs(self):
         command = Command()
         command.add_option("foo", Option("a", String()))