[New-bugs-announce] [issue25836] Documentation of MAKE_FUNCTION is still incorrect
Russell Keith-Magee
report at bugs.python.org
Thu Dec 10 23:13:55 EST 2015
New submission from Russell Keith-Magee:
Refs Issue16554, Issue13026, Issue14349, and probably others.
The documentation for the interpretation of the argc argument to MAKE_FUNCTION in Doc/library/dis.rst is incorrect.
As of 13 August 2015, the docs say:
"""
Pushes a new function object on the stack. From bottom to top, the consumed
stack must consist of:
* ``argc & 0xFF`` default argument objects in positional order
* ``(argc >> 8) & 0xFF`` pairs of name and default argument, with the name
just below the object on the stack, for keyword-only parameters
* ``(argc >> 16) & 0x7FFF`` parameter annotation objects
* a tuple listing the parameter names for the annotations (only if there are
ony annotation objects)
* the code associated with the function (at TOS1)
* the :term:`qualified name` of the function (at TOS)
"""
However, this doesn't capture the fact that:
* if there are annotations, the number of default arguments returned by `argc & 0xFF` must be reduced by `(argc >> 16) & 0x7FFF`
* The value `(argc >> 16) & 0x7FFF` for the number of annotations *includes* the "extra" entry for the tuple describing which arguments the annotations apply to. This means that `(argc >> 16) & 0x7FFF` will be either 0, or 2+; it can't be 1 (because if you have one annotation, you must also have a tuple describing which arguments is annotated).
----------
assignee: docs at python
components: Documentation
messages: 256189
nosy: docs at python, freakboy3742
priority: normal
severity: normal
status: open
title: Documentation of MAKE_FUNCTION is still incorrect
versions: Python 2.7, Python 3.2, Python 3.3, Python 3.4, Python 3.5, Python 3.6
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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue25836>
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