Added representation functions for statement and apply_filter for block, along with unit tests.

src/utils.py

@@ -17,6 +17,13 @@ class Statement:
         return self.stype == other.stype and self.name == other.name \
                 and self.args == other.args
 
+    def __str__(self):  # pragma: nocover
+        return '<Statement type=%s name=%s args=%s>' \
+                % (self.stype, self.name, self.args)
+
+    def __repr__(self):  # pragma: nocover
+        return str(self)
+
     def is_comment(self):
         return self.stype == 'comment'
 
@@ -120,6 +127,11 @@ class Block:
         self.statements = before + replacement + after
         self.pointer = start + len(replacement)
 
+    def apply_filter(self, callback):
+        """Apply a filter to the statement list. If the callback returns True,
+        the statement will remain in the list.."""
+        self.statements = filter(callback, self.statements)
+
 
 def find_leaders(statements):
     """Determine the leaders, which are:

tests/test_utils.py

@@ -11,9 +11,13 @@ class TestUtils(unittest.TestCase):
         self.statements = [add, S('command', 'j', 'foo'), add, add, \
                 S('label', 'foo')]
         self.block = B([S('command', 'foo'), \
-                        S('command', 'bar'),
+                        S('comment', 'bar'),
                         S('command', 'baz')])
 
+    def tearDown(self):
+        del self.statements
+        del self.block
+
     def test_find_leaders(self):
         self.assertEqual(find_leaders(self.statements), [0, 2, 4])
 
@@ -46,9 +50,12 @@ class TestUtils(unittest.TestCase):
         self.assertEqual(S('command', 'j', 'foo').jump_target(), 'foo')
         self.assertRaises(Exception, S('command', 'foo').jump_target)
 
+    def test_iter(self):
+        self.assertEqual(self.block.statements, list(self.block))
+
     def test_read(self):
         self.assertEqual(self.block.read(), S('command', 'foo'))
-        self.assertEqual(self.block.read(), S('command', 'bar'))
+        self.assertEqual(self.block.read(), S('comment', 'bar'))
         self.assertEqual(self.block.read(), S('command', 'baz'))
 
     def test_end(self):
@@ -61,13 +68,18 @@ class TestUtils(unittest.TestCase):
     def test_peek(self):
         self.assertEqual(self.block.peek(), S('command', 'foo'))
         self.assertEqual(self.block.peek(2), [S('command', 'foo'), \
-                                              S('command', 'bar')])
+                                              S('comment', 'bar')])
         self.block.read()
-        self.assertEqual(self.block.peek(), S('command', 'bar'))
+        self.assertEqual(self.block.peek(), S('comment', 'bar'))
 
     def test_replace(self):
         self.block.replace(1, [S('command', 'foobar')])
         self.assertEqual(self.block.pointer, 1)
         self.assertEqual(self.block.statements, [S('command', 'foobar'), \
-                                                 S('command', 'bar'), \
+                                                 S('comment', 'bar'), \
+                                                 S('command', 'baz')])
+
+    def test_apply_filter(self):
+        self.block.apply_filter(lambda s: s.is_command())
+        self.assertEqual(self.block.statements, [S('command', 'foo'), \
                                                  S('command', 'baz')])