[issue20456] Argument Clinic rollup patch, 2014/01/31

Larry Hastings report at bugs.python.org
Fri Jan 31 14:18:32 CET 2014


New submission from Larry Hastings:

Probably the last rollup patch for a while; I need to move on to code
reviewing.

Here's a list of changes in this patch:

* I added the oft-requested "rename the C variable for a parameter"
  functionality.  That works as follows:

     os.rename
         path as stinky: path_t

  Here the Python name is "path", and the C name is "stinky".
  Internally the "name" of the parameter is the Python name, and
  the "name" of the converter is the C name.  (But the converter
  gets the Python name too, because it needs it sometimes, e.g.
  for the keywords array.)

* Fixed a minor but difficult-to-fix problem: when cloning a function,
  the cloned function would still refer to the original function's
  name.  (You can see this in the PATH_T_INITIALIZE macros in
  os_replace in posixmodule.c.)

* While fixing the above I stumbled over a new problem: rendering
  often changes internal state of a parameter, which could cause
  problems if we clone an already-rendered parameter object.  The
  solution: make a copy of all the Parameter objects before rendering,
  then render from the copies.

* Fixing the above forced me to add a new initalizer to CConverter
  objects: pre_render(), which is called just before rendering.

* This change also means it's pretty important to call up to the super()
  for converter_init() and pre_render().

* Fixing the above also required new semantics for converter_init():
  you are no longer permitted to examine the function object in
  that method.  (I made it fail noisily with a "LandMine".)

* "clinic.py --converters" was broken, I fixed it.  (It was confused
  by object_converter having format_unit=None.)

* I fixed the unit tests too.

* You can now specify blank lines between directives without Clinic
  getting angry at you.

* I redid how I store all those little C code snippet template.
  Originally they were inline, but flush left, and that made
  reading them tiresome--the indent was jumping around on you.
  Changing to a central list removed the jumping around but now
  you had to scroll back and forth to correlate the template with
  where it was used.  The final solution: have them inline again,
  but indented, and simply outdent the text before use.  Go ahead,
  tell me that's *not* an improvement.  :D  (The outdenting function
  uses functools.lru_cache, so processing is really no slower.)

And last but certainly not least...!

Following a suggestion by Serhiy Storchaka, Argument Clinic is now
incredibly sophisticated with respect to #if'd out code.  In less than
200 lines, I wrote a reasonable C preprocessor monitor class.  The
monitor parses C files in parallel to Argument Clinic.  At any time
you can ask the monitor "what's the current preprocessor conditional
state?"  If the current code is potentially if'd out, Argument Clinic
uses the same conditional to potentially #if out the parser function,
the docstring, etc, when writing those to buffer or file.  It even
adds this to the end:

  #ifndef YOUR_FUNCTION_METHODDEF
      #define YOUR_FUNCTION_METHODDEF
  #endif /* !defined(YOUR_FUNCTION_METHODDEF) */

But *only* when necessary.

You can see this in action in the diff for Modules/clinic/zlibmodule.c.h.

I think this is a huge improvement!  (Thanks for the suggestion, Serhiy!)

----------
assignee: larry
files: larry.clinic.rollup.2014.01.31.1.diff
keywords: patch
messages: 209784
nosy: larry, ncoghlan, serhiy.storchaka, taleinat, zach.ware
priority: normal
severity: normal
stage: patch review
status: open
title: Argument Clinic rollup patch, 2014/01/31
type: enhancement
versions: Python 3.4
Added file: http://bugs.python.org/file33826/larry.clinic.rollup.2014.01.31.1.diff

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