Mailman 3 January 2017 - Python-checkins

cpython: Issue #28822: Add susp-ignored entry for NEWS; fix grammar
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/2b5e5a3a805e changeset: 106344:2b5e5a3a805e user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 23:37:56 2017 +0000 summary: Issue #28822: Add susp-ignored entry for NEWS; fix grammar files: Doc/tools/susp-ignored.csv | 1 + Misc/NEWS | 2 +- 2 files changed, 2 insertions(+), 1 deletions(-) diff --git a/Doc/tools/susp-ignored.csv b/Doc/tools/susp-ignored.csv --- a/Doc/tools/susp-ignored.csv +++ b/Doc/… [View More]

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cpython (merge 3.5 -> 3.6): Issues #11670: Merge configparser doc from 3.5
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/e06de6f9cfe5 changeset: 106341:e06de6f9cfe5 branch: 3.6 parent: 106340:1708afd284ff parent: 106339:e70882558a96 user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 23:36:39 2017 +0000 summary: Issues #11670: Merge configparser doc from 3.5 files: Doc/library/configparser.rst | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-) diff --git a/Doc/library/configparser.rst b/Doc/library/… [View More]

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cpython (merge 3.5 -> 3.6): Issues #29349: Merge Py 2.6+ compatibility from 3.5
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/1708afd284ff changeset: 106340:1708afd284ff branch: 3.6 parent: 106332:cdcb33f37bf3 parent: 106338:9880928ec962 user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 23:34:52 2017 +0000 summary: Issues #29349: Merge Py 2.6+ compatibility from 3.5 files: Doc/tools/extensions/patchlevel.py | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/Doc/tools/extensions/patchlevel.py b/Doc/tools/… [View More]

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cpython (3.5): Issue #11670: readfp(fp) parameter name is different to read_file(f)
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/e70882558a96 changeset: 106339:e70882558a96 branch: 3.5 user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 23:33:27 2017 +0000 summary: Issue #11670: readfp(fp) parameter name is different to read_file(f) files: Doc/library/configparser.rst | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-) diff --git a/Doc/library/configparser.rst b/Doc/library/configparser.rst --- a/Doc/library/configparser.rst ++… [View More]

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cpython (3.5): Issue #29349: Use __future__ print_function; Sphinx may use Python 2.6+
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/9880928ec962 changeset: 106338:9880928ec962 branch: 3.5 parent: 106330:ecdc864884a9 user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 23:33:13 2017 +0000 summary: Issue #29349: Use __future__ print_function; Sphinx may use Python 2.6+ files: Doc/tools/extensions/patchlevel.py | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/Doc/tools/extensions/patchlevel.py b/Doc/tools/extensions/… [View More]

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cpython (2.7): Issue #12067: Rewrite Comparisons section in the language reference
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/8a9904c5cb1d changeset: 106337:8a9904c5cb1d branch: 2.7 parent: 106325:b5125e971fdd user: Martin Panter <vadmium+py(a)gmail.com> date: Sat Jan 21 05:14:56 2017 +0000 summary: Issue #12067: Rewrite Comparisons section in the language reference Some of the details of comparing mixed types were incorrect or ambiguous. Added default behaviour and consistency suggestions for user-defined classes. Based on patch from Andy Maier. … [View More]files: Doc/reference/expressions.rst | 188 ++++++++++++++++++--- Misc/NEWS | 8 + 2 files changed, 163 insertions(+), 33 deletions(-) diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst --- a/Doc/reference/expressions.rst +++ b/Doc/reference/expressions.rst @@ -1058,10 +1058,6 @@ .. _comparisons: -.. _is: -.. _is not: -.. _in: -.. _not in: Comparisons =========== @@ -1101,39 +1097,98 @@ preferred; where ``!=`` is mentioned below ``<>`` is also accepted. The ``<>`` spelling is considered obsolescent. +Value comparisons +----------------- + The operators ``<``, ``>``, ``==``, ``>=``, ``<=``, and ``!=`` compare the -values of two objects. The objects need not have the same type. If both are -numbers, they are converted to a common type. Otherwise, objects of different -types *always* compare unequal, and are ordered consistently but arbitrarily. -You can control comparison behavior of objects of non-built-in types by defining -a ``__cmp__`` method or rich comparison methods like ``__gt__``, described in -section :ref:`specialnames`. +values of two objects. The objects do not need to have the same type. + +Chapter :ref:`objects` states that objects have a value (in addition to type +and identity). The value of an object is a rather abstract notion in Python: +For example, there is no canonical access method for an object's value. Also, +there is no requirement that the value of an object should be constructed in a +particular way, e.g. comprised of all its data attributes. Comparison operators +implement a particular notion of what the value of an object is. One can think +of them as defining the value of an object indirectly, by means of their +comparison implementation. + +Types can customize their comparison behavior by implementing +a :meth:`__cmp__` method or +:dfn:`rich comparison methods` like :meth:`__lt__`, described in +:ref:`customization`. + +The default behavior for equality comparison (``==`` and ``!=``) is based on +the identity of the objects. Hence, equality comparison of instances with the +same identity results in equality, and equality comparison of instances with +different identities results in inequality. A motivation for this default +behavior is the desire that all objects should be reflexive (i.e. ``x is y`` +implies ``x == y``). + +The default order comparison (``<``, ``>``, ``<=``, and ``>=``) gives a +consistent but arbitrary order. (This unusual definition of comparison was used to simplify the definition of operations like sorting and the :keyword:`in` and :keyword:`not in` operators. In the future, the comparison rules for objects of different types are likely to change.) -Comparison of objects of the same type depends on the type: +The behavior of the default equality comparison, that instances with different +identities are always unequal, may be in contrast to what types will need that +have a sensible definition of object value and value-based equality. Such +types will need to customize their comparison behavior, and in fact, a number +of built-in types have done that. -* Numbers are compared arithmetically. +The following list describes the comparison behavior of the most important +built-in types. -* Strings are compared lexicographically using the numeric equivalents (the - result of the built-in function :func:`ord`) of their characters. Unicode and - 8-bit strings are fully interoperable in this behavior. [#]_ +* Numbers of built-in numeric types (:ref:`typesnumeric`) and of the standard + library types :class:`fractions.Fraction` and :class:`decimal.Decimal` can be + compared within and across their types, with the restriction that complex + numbers do not support order comparison. Within the limits of the types + involved, they compare mathematically (algorithmically) correct without loss + of precision. -* Tuples and lists are compared lexicographically using comparison of - corresponding elements. This means that to compare equal, each element must - compare equal and the two sequences must be of the same type and have the same - length. +* Strings (instances of :class:`str` or :class:`unicode`) + compare lexicographically using the numeric equivalents (the + result of the built-in function :func:`ord`) of their characters. [#]_ + When comparing an 8-bit string and a Unicode string, the 8-bit string + is converted to Unicode. If the conversion fails, the strings + are considered unequal. - If not equal, the sequences are ordered the same as their first differing - elements. For example, ``cmp([1,2,x], [1,2,y])`` returns the same as - ``cmp(x,y)``. If the corresponding element does not exist, the shorter sequence - is ordered first (for example, ``[1,2] < [1,2,3]``). +* Instances of :class:`tuple` or :class:`list` can be compared only + within each of their types. Equality comparison across these types + results in unequality, and ordering comparison across these types + gives an arbitrary order. -* Mappings (dictionaries) compare equal if and only if their sorted (key, value) - lists compare equal. [#]_ Outcomes other than equality are resolved + These sequences compare lexicographically using comparison of corresponding + elements, whereby reflexivity of the elements is enforced. + + In enforcing reflexivity of elements, the comparison of collections assumes + that for a collection element ``x``, ``x == x`` is always true. Based on + that assumption, element identity is compared first, and element comparison + is performed only for distinct elements. This approach yields the same + result as a strict element comparison would, if the compared elements are + reflexive. For non-reflexive elements, the result is different than for + strict element comparison. + + Lexicographical comparison between built-in collections works as follows: + + - For two collections to compare equal, they must be of the same type, have + the same length, and each pair of corresponding elements must compare + equal (for example, ``[1,2] == (1,2)`` is false because the type is not the + same). + + - Collections are ordered the same as their + first unequal elements (for example, ``cmp([1,2,x], [1,2,y])`` returns the + same as ``cmp(x,y)``). If a corresponding element does not exist, the + shorter collection is ordered first (for example, ``[1,2] < [1,2,3]`` is + true). + +* Mappings (instances of :class:`dict`) compare equal if and only if they have + equal `(key, value)` pairs. Equality comparison of the keys and elements + enforces reflexivity. + + Outcomes other than equality are resolved consistently, but are not otherwise defined. [#]_ * Most other objects of built-in types compare unequal unless they are the same @@ -1141,8 +1196,59 @@ another one is made arbitrarily but consistently within one execution of a program. +User-defined classes that customize their comparison behavior should follow +some consistency rules, if possible: + +* Equality comparison should be reflexive. + In other words, identical objects should compare equal: + + ``x is y`` implies ``x == y`` + +* Comparison should be symmetric. + In other words, the following expressions should have the same result: + + ``x == y`` and ``y == x`` + + ``x != y`` and ``y != x`` + + ``x < y`` and ``y > x`` + + ``x <= y`` and ``y >= x`` + +* Comparison should be transitive. + The following (non-exhaustive) examples illustrate that: + + ``x > y and y > z`` implies ``x > z`` + + ``x < y and y <= z`` implies ``x < z`` + +* Inverse comparison should result in the boolean negation. + In other words, the following expressions should have the same result: + + ``x == y`` and ``not x != y`` + + ``x < y`` and ``not x >= y`` (for total ordering) + + ``x > y`` and ``not x <= y`` (for total ordering) + + The last two expressions apply to totally ordered collections (e.g. to + sequences, but not to sets or mappings). See also the + :func:`~functools.total_ordering` decorator. + +* The :func:`hash` result should be consistent with equality. + Objects that are equal should either have the same hash value, + or be marked as unhashable. + +Python does not enforce these consistency rules. + + +.. _in: +.. _not in: .. _membership-test-details: +Membership test operations +-------------------------- + The operators :keyword:`in` and :keyword:`not in` test for collection membership. ``x in s`` evaluates to true if *x* is a member of the collection *s*, and false otherwise. ``x not in s`` returns the negation of ``x in s``. @@ -1192,6 +1298,13 @@ operator: is not pair: identity; test + +.. _is: +.. _is not: + +Identity comparisons +-------------------- + The operators :keyword:`is` and :keyword:`is not` test for object identity: ``x is y`` is true if and only if *x* and *y* are the same object. ``x is not y`` yields the inverse truth value. [#]_ @@ -1418,15 +1531,24 @@ cases, Python returns the latter result, in order to preserve that ``divmod(x,y)[0] * y + x % y`` be very close to ``x``. -.. [#] While comparisons between unicode strings make sense at the byte - level, they may be counter-intuitive to users. For example, the - strings ``u"\u00C7"`` and ``u"\u0043\u0327"`` compare differently, - even though they both represent the same unicode character (LATIN - CAPITAL LETTER C WITH CEDILLA). To compare strings in a human - recognizable way, compare using :func:`unicodedata.normalize`. +.. [#] The Unicode standard distinguishes between :dfn:`code points` + (e.g. U+0041) and :dfn:`abstract characters` (e.g. "LATIN CAPITAL LETTER A"). + While most abstract characters in Unicode are only represented using one + code point, there is a number of abstract characters that can in addition be + represented using a sequence of more than one code point. For example, the + abstract character "LATIN CAPITAL LETTER C WITH CEDILLA" can be represented + as a single :dfn:`precomposed character` at code position U+00C7, or as a + sequence of a :dfn:`base character` at code position U+0043 (LATIN CAPITAL + LETTER C), followed by a :dfn:`combining character` at code position U+0327 + (COMBINING CEDILLA). -.. [#] The implementation computes this efficiently, without constructing lists or - sorting. + The comparison operators on unicode strings compare at the level of Unicode code + points. This may be counter-intuitive to humans. For example, + ``u"\u00C7" == u"\u0043\u0327"`` is ``False``, even though both strings + represent the same abstract character "LATIN CAPITAL LETTER C WITH CEDILLA". + + To compare strings at the level of abstract characters (that is, in a way + intuitive to humans), use :func:`unicodedata.normalize`. .. [#] Earlier versions of Python used lexicographic comparison of the sorted (key, value) lists, but this was very expensive for the common case of comparing for diff --git a/Misc/NEWS b/Misc/NEWS --- a/Misc/NEWS +++ b/Misc/NEWS @@ -73,6 +73,14 @@ - Issue #27867: Function PySlice_GetIndicesEx() is replaced with a macro. +Documentation +------------- + +- Issue #12067: Rewrite Comparisons section in the Expressions chapter of the + language reference. Some of the details of comparing mixed types were + incorrect or ambiguous. Added default behaviour and consistency suggestions + for user-defined classes. Based on patch from Andy Maier. + Build ----- -- Repository URL: https://hg.python.org/cpython [View Less]

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cpython: Issues #29349: Add NEWS for 3.7; use “with” statement
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/ca7d2af9920e changeset: 106335:ca7d2af9920e user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 10:17:17 2017 +0000 summary: Issues #29349: Add NEWS for 3.7; use “with” statement files: Doc/tools/extensions/patchlevel.py | 5 +---- Misc/NEWS | 2 ++ 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/Doc/tools/extensions/patchlevel.py b/Doc/tools/extensions/patchlevel.py --- a/Doc/… [View More]

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cpython: Issue #29384: Remove Be OS scripts from Modules/, unused in 3.0+
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/aa9aef656fe0 changeset: 106336:aa9aef656fe0 user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 10:21:57 2017 +0000 summary: Issue #29384: Remove Be OS scripts from Modules/, unused in 3.0+ files: Misc/NEWS | 2 + Modules/ar_beos | 73 ------------------------------- Modules/ld_so_beos | 78 ---------------------------------- 3 files changed, 2 insertions(+), 151 deletions(-) diff --git a/Misc/NEWS b/… [View More]Misc/NEWS --- a/Misc/NEWS +++ b/Misc/NEWS @@ -675,6 +675,8 @@ Build ----- +- Issue #29384: Remove old Be OS helper scripts. + - Issue #26851: Set Android compilation and link flags. - Issue #28768: Fix implicit declaration of function _setmode. Patch by diff --git a/Modules/ar_beos b/Modules/ar_beos deleted file mode 100755 --- a/Modules/ar_beos +++ /dev/null @@ -1,73 +0,0 @@ -#!/bin/sh -# -# Truly fake ar, using a directory to store object files. -# -# Donn Cave, donn(a)oz.net - -usage='Usage: ar-fake cr libpython.dir obj.o ... - ar-fake d libpython.dir obj.o ... - ar-fake so libpython.dir libpython.so' - -case $# in -0|1|2) - echo "$usage" >&2 - exit 1 - ;; -esac - -command=$1 -library=$2 -shift 2 - -case $command in -cr) - if test -d $library - then : - else - mkdir $library - fi - if cp -p $* $library - then - # To force directory modify date, create or delete a file. - if test -e $library/.tch - then rm $library/.tch - else echo tch > $library/.tch - fi - exit 0 - fi - ;; -d) - if test -d $library - then - cd $library - rm -f $* - fi - ;; -so) - case $BE_HOST_CPU in - ppc) - # In case your libpython.a refers to any exotic libraries, - # mwld needs to know that here. The following hack makes - # a couple of assumptions about Modules/Makefile. If it - # doesn't work, you may as well add the necessary libraries - # here explicitly instead. - extralibs=$( - (cd Modules; make -f Makefile -n link) | - sed -n 's/.*\.so $.*$ -o python.*/\1/p' - ) - mwld -xms -export pragma -nodup -o $1 $library/* $extralibs - ;; - x86) - ld -shared -soname $(basename $1) -o $1 $library/* - ;; - esac - status=$? - cd $(dirname $1) - ln -sf $PWD lib - exit $status - ;; -*) - echo "$usage" >&2 - exit 1 - ;; -esac diff --git a/Modules/ld_so_beos b/Modules/ld_so_beos deleted file mode 100755 --- a/Modules/ld_so_beos +++ /dev/null @@ -1,78 +0,0 @@ -#! /bin/sh -# -# linkmodule for Python -# Chris Herborth (chrish(a)qnx.com) -# -# This is covered by the same copyright/licensing terms as the rest of -# Python. -# -# Shell script to build shared library versions of the modules; since -# the change to the *ahem* "proper" import/export mechanism, this script -# is much simpler. It handles PowerPC and x86, too. -# -# This is called by the Modules/Makefile as $(LDSHARED): -# -# $(LDSHARED) foomodule.o -o foomodule$(SO) -# -# Could also be called as: -# -# $(LDSHARED) readline.o -L/boot/home/config/lib -lreadline -ltermcap \ -# -o readline$(SO) -# -# so we need to preserve the arguments, sort of. - -# Make sure we got reasonable arguments. -TARGET="" -ARGS="" - -while [ "$#" != "0" ]; do - case "$1" in - -o) TARGET="$2"; shift; shift;; - *) ARGS="$ARGS $1"; shift;; - esac -done - -if [ "$TARGET" = "" ] ; then - echo "Usage:" - echo - echo " $0 [args] -o foomodule.so [args] foomodule.o [args]" - echo - echo "Where:" - echo - echo " [args] normal compiler arguments" - exit 1 -fi - -# The shared libraries and glue objects we need to link against; these -# libs are overkill for most of the standard modules, but it makes life -# in this shell script easier. -LIBS="-lbe -lnet -lroot" - -case $BE_HOST_CPU in - ppc) - # Boy, do we need a lot of crap... - GLUE_LOC=/boot/develop/lib/ppc - GLUE="${GLUE_LOC}/glue-noinit.a ${GLUE_LOC}/init_term_dyn.o" - case $(uname -r) in - 4.0*) CC="mwcc -xms -export pragma -nodup" ;; - *) CC="mwcc -shared -export pragma -nodup" ;; - esac - ;; - - x86) - # We don't need as much crap here... - GLUE="" - CC="gcc -nostart -Wl,-soname=${TARGET}" - ;; - - *) - # What the?!? - echo "$0 doesn't support $BE_HOST_CPU systems..." - echo "You're on your own... I'd be surprised if this works." - GLUE="" - CC="cc" - ;; -esac - -# Now link that shared lib... -$CC -o $TARGET $ARGS $GLUE $LIBS -- Repository URL: https://hg.python.org/cpython [View Less]

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cpython (merge 3.6 -> default): Issues #29349: Merge Py 2 fix 3.6
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/db8b917bbfdd changeset: 106334:db8b917bbfdd parent: 106333:9dbb7bbc1449 parent: 106332:cdcb33f37bf3 user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 10:16:28 2017 +0000 summary: Issues #29349: Merge Py 2 fix 3.6 files: Doc/tools/extensions/patchlevel.py | 4 ++-- Misc/NEWS | 5 +++++ 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/Doc/tools/extensions/patchlevel.py b/… [View More]

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cpython (merge 3.6 -> default): Issues #12067: Merge hash recommendation from 3.6
by martin.panter Jan. 29, 2017

Jan. 29, 2017

https://hg.python.org/cpython/rev/9dbb7bbc1449 changeset: 106333:9dbb7bbc1449 parent: 106328:9e9f292c65ec parent: 106331:9702c5f08df1 user: Martin Panter <vadmium+py(a)gmail.com> date: Sun Jan 29 10:10:30 2017 +0000 summary: Issues #12067: Merge hash recommendation from 3.6 files: Doc/reference/expressions.rst | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst --- a/Doc/… [View More]

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