Use generators in the byte code parsing. __next__? yikes!

2 files changed, 25 insertions, 42 deletions

diff --git a/coverage/bytecode.py b/coverage/bytecode.py
index fd5c7da2..06bc1dfd 100644
--- a/coverage/bytecode.py
+++ b/coverage/bytecode.py
@@ -30,7 +30,6 @@ class ByteCodes(object):
     # pylint: disable=R0924
     def __init__(self, code):
         self.code = code
-        self.offset = 0
 
     if sys.version_info >= (3, 0):
         def __getitem__(self, i):
@@ -40,32 +39,26 @@ class ByteCodes(object):
             return ord(self.code[i])
 
     def __iter__(self):
-        return self
+        offset = 0
+        while offset < len(self.code):
+            bc = ByteCode()
+            bc.op = self[offset]
+            bc.offset = offset
 
-    def __next__(self):
-        if self.offset >= len(self.code):
-            raise StopIteration
+            next_offset = offset+1
+            if bc.op >= opcode.HAVE_ARGUMENT:
+                bc.arg = self[offset+1] + 256*self[offset+2]
+                next_offset += 2
 
-        bc = ByteCode()
-        bc.op = self[self.offset]
-        bc.offset = self.offset
+                label = -1
+                if bc.op in opcode.hasjrel:
+                    label = next_offset + bc.arg
+                elif bc.op in opcode.hasjabs:
+                    label = bc.arg
+                bc.jump_to = label
 
-        next_offset = self.offset+1
-        if bc.op >= opcode.HAVE_ARGUMENT:
-            bc.arg = self[self.offset+1] + 256*self[self.offset+2]
-            next_offset += 2
-
-            label = -1
-            if bc.op in opcode.hasjrel:
-                label = next_offset + bc.arg
-            elif bc.op in opcode.hasjabs:
-                label = bc.arg
-            bc.jump_to = label
-
-        bc.next_offset = self.offset = next_offset
-        return bc
-
-    next = __next__     # Py2k uses an old-style non-dunder name.
+            bc.next_offset = offset = next_offset
+            yield bc
 
 
 class CodeObjects(object):
@@ -74,18 +67,11 @@ class CodeObjects(object):
         self.stack = [code]
 
     def __iter__(self):
-        return self
-
-    def __next__(self):
-        if self.stack:
+        while self.stack:
             # We're going to return the code object on the stack, but first
             # push its children for later returning.
             code = self.stack.pop()
             for c in code.co_consts:
                 if isinstance(c, types.CodeType):
                     self.stack.append(c)
-            return code
-
-        raise StopIteration
-
-    next = __next__
+            yield code
diff --git a/coverage/parser.py b/coverage/parser.py
index 44455054..bb6b6082 100644
--- a/coverage/parser.py
+++ b/coverage/parser.py
@@ -381,27 +381,25 @@ class ByteParser(object):
         """Map byte offsets to line numbers in `code`.
 
         Uses co_lnotab described in Python/compile.c to map byte offsets to
-        line numbers.  Returns a list: [(b0, l0), (b1, l1), ...]
+        line numbers.  Produces a sequence: (b0, l0), (b1, l1), ...
 
         """
         # Adapted from dis.py in the standard library.
         byte_increments = self._lnotab_increments(self.code.co_lnotab[0::2])
         line_increments = self._lnotab_increments(self.code.co_lnotab[1::2])
 
-        bytes_lines = []
         last_line_num = None
         line_num = self.code.co_firstlineno
         byte_num = 0
         for byte_incr, line_incr in zip(byte_increments, line_increments):
             if byte_incr:
                 if line_num != last_line_num:
-                    bytes_lines.append((byte_num, line_num))
+                    yield (byte_num, line_num)
                     last_line_num = line_num
                 byte_num += byte_incr
             line_num += line_incr
         if line_num != last_line_num:
-            bytes_lines.append((byte_num, line_num))
-        return bytes_lines
+            yield (byte_num, line_num)
 
     def _find_statements(self):
         """Find the statements in `self.code`.
@@ -426,7 +424,6 @@ class ByteParser(object):
         Returns a list of `Chunk` objects.
 
         """
-
         # The list of chunks so far, and the one we're working on.
         chunks = []
         chunk = None
@@ -634,11 +631,11 @@ class ByteParser(object):
 
 
 class Chunk(object):
-    """A sequence of bytecodes with a single entrance.
+    """A sequence of byte codes with a single entrance.
 
     To analyze byte code, we have to divide it into chunks, sequences of byte
-    codes such that each basic block has only one entrance, the first
-    instruction in the block.
+    codes such that each chunk has only one entrance, the first instruction in
+    the block.
 
     This is almost the CS concept of `basic block`_, except that we're willing
     to have many exits from a chunk, and "basic block" is a more cumbersome