Merged revisions 72487-72488,72879 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

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  r72487 | jeffrey.yasskin | 2009-05-08 17:51:06 -0400 (Fri, 08 May 2009) | 7 lines

  PyCode_NewEmpty:
  Most uses of PyCode_New found by http://www.google.com/codesearch?q=PyCode_New
  are trying to build an empty code object, usually to put it in a dummy frame
  object. This patch adds a PyCode_NewEmpty wrapper which lets the user specify
  just the filename, function name, and first line number, instead of also
  requiring lots of code internals.
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  r72488 | jeffrey.yasskin | 2009-05-08 18:23:21 -0400 (Fri, 08 May 2009) | 13 lines

  Issue 5954, PyFrame_GetLineNumber:
  Most uses of PyCode_Addr2Line
  (http://www.google.com/codesearch?q=PyCode_Addr2Line) are just trying to get
  the line number of a specified frame, but there's no way to do that directly.
  Forcing people to go through the code object makes them know more about the
  guts of the interpreter than they should need.

  The remaining uses of PyCode_Addr2Line seem to be getting the line from a
  traceback (for example,
  http://www.google.com/codesearch/p?hl=en#u_9_nDrchrw/pygame-1.7.1release/src/base.c&q=PyCode_Addr2Line),
  which is replaced by the tb_lineno field.  So we may be able to deprecate
  PyCode_Addr2Line entirely for external use.
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  r72879 | jeffrey.yasskin | 2009-05-23 19:23:01 -0400 (Sat, 23 May 2009) | 14 lines

  Issue #6042:
  lnotab-based tracing is very complicated and isn't documented very well.  There
  were at least 3 comment blocks purporting to document co_lnotab, and none did a
  very good job. This patch unifies them into Objects/lnotab_notes.txt which
  tries to completely capture the current state of affairs.

  I also discovered that we've attached 2 layers of patches to the basic tracing
  scheme. The first layer avoids jumping to instructions that don't start a line,
  to avoid problems in if statements and while loops.  The second layer
  discovered that jumps backward do need to trace at instructions that don't
  start a line, so it added extra lnotab entries for 'while' and 'for' loops, and
  added a special case for backward jumps within the same line. I replaced these
  patches by just treating forward and backward jumps differently.
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1 files changed, 50 insertions, 0 deletions

diff --git a/Doc/c-api/code.rst b/Doc/c-api/code.rst
new file mode 100644
index 0000000..c6ca8c5
--- /dev/null
+++ b/Doc/c-api/code.rst
@@ -0,0 +1,50 @@
+.. highlightlang:: c
+
+.. _codeobjects:
+
+Code Objects
+------------
+
+.. sectionauthor:: Jeffrey Yasskin <jyasskin@gmail.com>
+
+
+.. index::
+   object: code
+
+Code objects are a low-level detail of the CPython implementation.
+Each one represents a chunk of executable code that hasn't yet been
+bound into a function.
+
+.. ctype:: PyCodeObject
+
+   The C structure of the objects used to describe code objects.  The
+   fields of this type are subject to change at any time.
+
+
+.. cvar:: PyTypeObject PyCode_Type
+
+   This is an instance of :ctype:`PyTypeObject` representing the Python
+   :class:`code` type.
+
+
+.. cfunction:: int PyCode_Check(PyObject *co)
+
+   Return true if *co* is a :class:`code` object
+
+.. cfunction:: int PyCode_GetNumFree(PyObject *co)
+
+   Return the number of free variables in *co*.
+
+.. cfunction:: PyCodeObject *PyCode_New(int argcount, int nlocals, int stacksize, int flags, PyObject *code, PyObject *consts, PyObject *names, PyObject *varnames, PyObject *freevars, PyObject *cellvars, PyObject *filename, PyObject *name, int firstlineno, PyObject *lnotab)
+
+   Return a new code object.  If you need a dummy code object to
+   create a frame, use :cfunc:`PyCode_NewEmpty` instead.  Calling
+   :cfunc:`PyCode_New` directly can bind you to a precise Python
+   version since the definition of the bytecode changes often.
+
+
+.. cfunction:: int PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno)
+
+   Return a new empty code object with the specified filename,
+   function name, and first line number.  It is illegal to
+   :keyword:`exec` or :func:`eval` the resulting code object.