[pypy-svn] r48302 - pypy/dist/pypy/lang/smalltalk

[cfbolz at codespeak.net]

Author: cfbolz
Date: Sun Nov  4 22:46:44 2007
New Revision: 48302

Modified:
   pypy/dist/pypy/lang/smalltalk/interpreter.py
Log:
try to replace some of adrian's questions by explanations what is going on.


Modified: pypy/dist/pypy/lang/smalltalk/interpreter.py
==============================================================================
--- pypy/dist/pypy/lang/smalltalk/interpreter.py	(original)
+++ pypy/dist/pypy/lang/smalltalk/interpreter.py	Sun Nov  4 22:46:44 2007
@@ -42,7 +42,8 @@
 
     def step(self):
         next = self.w_active_context.getNextBytecode()
-        # AK please explain this cond 
+        # we_are_translated returns false on top of CPython and true when
+        # translating the interpreter
         if not objectmodel.we_are_translated():
             bytecodeimpl = BYTECODE_TABLE[next]
             if self._w_last_active_context != self.w_active_context:
@@ -65,7 +66,10 @@
                     next, bytecodeimpl.__name__,)
             bytecodeimpl(self.w_active_context, self)
         else:
-            # AK does not understand below
+            # this is a performance optimization: when translating the
+            # interpreter, the bytecode dispatching is not implemented as a
+            # list lookup and an indirect call but as a switch. The for loop
+            # below produces the switch (by being unrolled).
             for code, bytecodeimpl in unrolling_bytecode_table:
                 if code == next:
                     bytecodeimpl(self.w_active_context, self)
@@ -81,7 +85,7 @@
 #
 # "self" is always a W_ContextPart instance.  
 
-# AK does not understand __extend__
+# __extend__ adds new methods to the W_ContextPart class
 class __extend__(W_ContextPart):
     # push bytecodes
     def pushReceiverVariableBytecode(self, interp):