Size: 1283
Comment: Add link to other 3.0 page
|
Size: 3438
Comment:
|
Deletions are marked like this. | Additions are marked like this. |
Line 5: | Line 5: |
* Reduce feature duplication: * string module vs. string methods * xrange() vs range() * int vs. long * 8 bit vs. Unicode strings * map/filter/reduce vs. list comprehensions * lambda vs. def * Library reorganization * Return iterators instead of lists * d.keys(), .values(), .items() * range(), zip(), map(), filter() * Consume iterators * min(), max() * Optional static typing? * Support only new-style classes; classic classes will be gone. * Remove string exceptions, `x` for repr(x), sys.exc_type, coerce(), other deprecated stuff * print as a function -- write(x,y,z), writeln(x,y,z) |
== Core Language Changes == |
Line 23: | Line 7: |
See the "Python Regrets" talk and other recent presentations by Guido. | * Remove distinction between `int` and `long` types. [[#a 4]] * Make all strings unicode, and have a separate bytes type. [[#a 2]] [[#a 4]] * Replace all old-style classes. [[#a 4]] * Make the `exec` statement a function (again.) [[#a 1]] * Make the `print` statement a function. (`write(x,y,z), writeln(x,y,z)`) [[#a 1]] * Perhaps have optional declarations for static typing. * Do something so you can catch multiple exceptions using `except E1, E2, E3:`. Perhaps use `except E1, E2, E3 as err:` if you want the error variable. (Added by GvR, suggested by Bram Cohen.) * Add a `with` statement: {{{ with self: .foo = [1, 2, 3] .bar(4, .foo) }}} |
Line 25: | Line 20: |
== Rearrangements == | * Remove {{{`x`}}}. [[#a 1]] Alternatively: use `repr(x)`. Reasoning: backticks are hard to read in many fonts and can be mangled by typesetting software. * Remove the `lambda` statement. [[#a 1]] [[#a 4]] Alternatively: use a local function. Reasoning: `lambda` supports only one statement. * Remove support for string exceptions. [[#a 1]] Alternatively: use a class. |
Line 27: | Line 29: |
intern(), id(): put in sys | == Built-In Changes == |
Line 29: | Line 31: |
xrange(): make range() return an iterator | * Have `range()`, `zip()`, `dict.keys()`, `dict.items()`, and `dict.values()` return iterators. * Move `compile()`, `intern()` and `id()` to the `sys` module. [[#a 1]] * Change `max()` and `min()` to consume iterators. |
Line 31: | Line 35: |
buffer(): must die (use bytes, PEP 296) | * Remove `dict.iteritems()`, `dict.iterkeys()`, and `dict.itervalues()`. Alternatively: use `dict.items()`, `dict.keys()`, and `dict.values()` respectively. * Remove `apply()`. [[#a 1]] Alternatively: use `f(*args, **kw)`. * Remove `xrange()`. [[#a 1]] [[#a 4]] Alternatively: use `range()`. * Remove `map()` and `filter()`. [[#a 1]] [[#a 4]] Alternatively: use list comprehensions. * Remove `coerce()` as it is obsolete. [[#a 1]] * Remove `reduce()`. [[#a 1]] Alternatively: use a loop. * Remove `callable()`. [[#a 1]] Alternatively: catch the exception. * Remove `buffer()`. [[#a 1]] [[#a 2]] Alternatively: use new `bytes` type. * Remove `raw_input()`. [[#a 1]] Alternatively: use `sys.stdin.readline()`. * Remove `input()`. [[#a 1]] Alternatively: use `eval(sys.stdin.readline())`. * Remove `execfile()` and `reload()`. [[#a 1]] Alternatively: use `exec()`. |
Line 33: | Line 57: |
raw_input(): use sys.stdin.readline() | == Standard Library Changes == |
Line 35: | Line 59: |
input(): use eval(sys.stdin.readline()) | * Remove `string` module. [[#c 4]] Alternatively: use string methods. * Remove other deprecated modules. [[#c 3]] * Remove `sys.exc_type`. [[#a 1]] Alternatively: use `sys.exc_info`. Reason: as it is not thread safe. |
Line 37: | Line 66: |
callable(): just call it, already | == Unresolved Issues == |
Line 39: | Line 68: |
execfile(), reload(): use exec() | * `L += x` and `L.extend(x)` are equivalent. * Can the order of parameter of the `insert` method be changed so the the index parameter is optional and `list.append` can be removed? * What is the status of the `<>` operator? |
Line 41: | Line 72: |
compile(): put in sys | == References == |
Line 43: | Line 74: |
exec as a statement is not worth it -- make it a function |
* [[Anchor(a)]] [1] Python Regrets: http://www.python.org/doc/essays/ppt/regrets/PythonRegrets.pdf * [[Anchor(b)]] [2] PEP 296 -- Adding a bytes Object Type: http://python.org/peps/pep-0296.html * [[Anchor(c)]] [3] PEP 4 -- Deprecation of Standard Modules: http://python.org/peps/pep-0004.html * [[Anchor(d)]] [4] PyCon 2003 State of the Union Address: http://www.python.org/doc/essays/ppt/pycon2003/pycon2003.ppt |
This page lists features that GvR has mentioned as goals for Python 3.0.
(Another list is at PythonThreeDotOh, but it incorporates items that GvR has never talked about.)
Core Language Changes
Remove distinction between int and long types. #a 4
Make all strings unicode, and have a separate bytes type. #a 2 #a 4
Replace all old-style classes. #a 4
Make the exec statement a function (again.) #a 1
Make the print statement a function. (write(x,y,z), writeln(x,y,z)) #a 1
- Perhaps have optional declarations for static typing.
Do something so you can catch multiple exceptions using except E1, E2, E3:. Perhaps use except E1, E2, E3 as err: if you want the error variable. (Added by GvR, suggested by Bram Cohen.)
Add a with statement:
with self: .foo = [1, 2, 3] .bar(4, .foo)
Remove `x`. #a 1
Alternatively: use repr(x). Reasoning: backticks are hard to read in many fonts and can be mangled by typesetting software.
Remove the lambda statement. #a 1 #a 4
- Alternatively: use a local function.
Reasoning: lambda supports only one statement.
- Alternatively: use a local function.
Remove support for string exceptions. #a 1
- Alternatively: use a class.
Built-In Changes
Have range(), zip(), dict.keys(), dict.items(), and dict.values() return iterators.
Move compile(), intern() and id() to the sys module. #a 1
Change max() and min() to consume iterators.
Remove dict.iteritems(), dict.iterkeys(), and dict.itervalues().
Alternatively: use dict.items(), dict.keys(), and dict.values() respectively.
Remove apply(). #a 1
Alternatively: use f(*args, **kw).
Alternatively: use range().
Remove map() and filter(). #a 1 #a 4
- Alternatively: use list comprehensions.
Remove coerce() as it is obsolete. #a 1
Remove reduce(). #a 1
- Alternatively: use a loop.
Remove callable(). #a 1
- Alternatively: catch the exception.
Alternatively: use new bytes type.
Remove raw_input(). #a 1
Alternatively: use sys.stdin.readline().
Remove input(). #a 1
Alternatively: use eval(sys.stdin.readline()).
Remove execfile() and reload(). #a 1
Alternatively: use exec().
Standard Library Changes
Remove string module. #c 4
- Alternatively: use string methods.
Remove other deprecated modules. #c 3
Remove sys.exc_type. #a 1
Alternatively: use sys.exc_info. Reason: as it is not thread safe.
Unresolved Issues
L += x and L.extend(x) are equivalent.
Can the order of parameter of the insert method be changed so the the index parameter is optional and list.append can be removed?
What is the status of the <> operator?
References
Anchor(a) [1] Python Regrets: http://www.python.org/doc/essays/ppt/regrets/PythonRegrets.pdf
Anchor(b) [2] PEP 296 -- Adding a bytes Object Type: http://python.org/peps/pep-0296.html
Anchor(c) [3] PEP 4 -- Deprecation of Standard Modules: http://python.org/peps/pep-0004.html
Anchor(d) [4] PyCon 2003 State of the Union Address: http://www.python.org/doc/essays/ppt/pycon2003/pycon2003.ppt