add a SETUP_WITH opcode
It speeds up the with statement and correctly looks up the special
methods involved.
diff --git a/Doc/library/dis.rst b/Doc/library/dis.rst
index 6b7ed1e..9bd65dd 100644
--- a/Doc/library/dis.rst
+++ b/Doc/library/dis.rst
@@ -532,6 +532,18 @@
the names of the base classes, and TOS2 the class name.
+.. opcode:: SETUP_WITH (delta)
+
+ This opcode performs several operations before a with block starts. First,
+ it loads :meth:`~object.__exit__` from the context manager and pushes it onto
+ the stack for later use by :opcode:`WITH_CLEANUP`. Then,
+ :meth:`~object.__enter__` is called, and a finally block pointing to *delta*
+ is pushed. Finally, the result of calling the enter method is pushed onto
+ the stack. The next opcode will either ignore it (:opcode:`POP_TOP`), or
+ store it in (a) variable(s) (:opcode:`STORE_FAST`, :opcode:`STORE_NAME`, or
+ :opcode:`UNPACK_SEQUENCE`).
+
+
.. opcode:: WITH_CLEANUP ()
Cleans up the stack when a :keyword:`with` statement block exits. On top of
diff --git a/Doc/reference/compound_stmts.rst b/Doc/reference/compound_stmts.rst
index 3c716b2..afb7ebc 100644
--- a/Doc/reference/compound_stmts.rst
+++ b/Doc/reference/compound_stmts.rst
@@ -339,6 +339,8 @@
#. The context expression is evaluated to obtain a context manager.
+#. The context manager's :meth:`__exit__` is loaded for later use.
+
#. The context manager's :meth:`__enter__` method is invoked.
#. If a target was included in the :keyword:`with` statement, the return value
@@ -349,7 +351,7 @@
The :keyword:`with` statement guarantees that if the :meth:`__enter__` method
returns without an error, then :meth:`__exit__` will always be called. Thus, if
an error occurs during the assignment to the target list, it will be treated the
- same as an error occurring within the suite would be. See step 5 below.
+ same as an error occurring within the suite would be. See step 6 below.
#. The suite is executed.