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...operations that are not directly related to the grammar. To indicate these actions each alternative can be followed by the action code inside curly-braces, which specifies the return value of the alternative: rule_name[return_type]: | first_alt1 first_alt2 { first_alt1 } | second_alt1 second_alt2 { second_alt1 } If the action is omitted and C code is being generated, then there are two different possibilities: If there’s a single name in the alternative, this gets returned. If not, a ...
...Atomic File Atomic Socket FreeBSD 8.3 (2012) X Linux 2.6.23 (2007) 2.6.27 (2008) Mac OS X 10.8 (2012) X NetBSD 6.1 (?) 6.0 (2012) OpenBSD 5.0 (2011) 5.2 (2012) Solaris 11 (2011) X Windows XP (2001) Seven SP1 (2011), 2008 R2 SP1 (2011) Legend: "Atomic File": first version of the operating system supporting creating atomically a non-inheritable file descriptor using open() "Atomic Socket": first version of the operating system supporting creating atomically a non-inheritable socket "X...
...atomic] open() with O_CLOEXEC flag [atomic] open() + os.set_cloexec(fd, True) [best-effort] os.dup() Windows: DuplicateHandle() [atomic] fcntl(fd, F_DUPFD_CLOEXEC) [atomic] dup() + os.set_cloexec(fd, True) [best-effort] os.dup2() fcntl(fd, F_DUP2FD_CLOEXEC, fd2) [atomic] dup3() with O_CLOEXEC flag [atomic] dup2() + os.set_cloexec(fd, True) [best-effort] os.pipe() Windows: CreatePipe() with SECURITY_ATTRIBUTES.bInheritHandle=TRUE, or _pipe() with O_NOINHERIT flag [atomic] pipe2() with...
...atomic (http://java.sun.com/javase/6/docs/api/java/util/concurrent/atomic/package-summary.html) [6]C++ Atomic Types and Operations, Hans Boehm and Lawrence Crowl (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2427.html) [7]__slots__ (http://docs.python.org/ref/slots.html) [8]Alternatives to SC, a thread on the cpp-threads mailing list, which includes lots of good examples. (http://www.decadentplace.org.uk/pipermail/cpp-threads/2007-January/001287.html) [9]python-sa...
...operations that are currently atomic remain atomic. The standard library As the standard library is not directly tied to the language definition it is not covered by this moratorium. Backports of 3.x features to 2.x The moratorium only affects features that would be new in 3.x. Import semantics For example, PEP 382. After all, import semantics vary between Python implementations anyway. Retroactive It is important to note that the moratorium covers all changes since the release o...
...operations may only be used in a "load" context. That is, a?.b = 1 and a?[b] = 1 will raise SyntaxError. Use earlier in the expression (a?.b.c = 1) is permitted, though unlikely to be useful unless combined with a coalescing operation: (a?.b ?? d).c = 1 Reading expressions For the maybe-dot and maybe-subscript operators, the intention is that expressions including these operators should be read and interpreted as for the regular versions of these operators. In "normal" cases, the end result...
...Atomic Types Remove distinction between int and long types; 'long' built-in type and literals with 'L' or 'l' suffix disappear [1] [done] Make all strings be Unicode, and have a separate bytes() type [1] The new string type will be called 'str'. See PEP 3137. [done] Return iterable views instead of lists where appropriate for atomic type methods (e.g. dict.keys(), dict.values(), dict.items(), etc.); iter* methods will be removed. [done] Make string.join() stringify its arguments? [18] [NO] Fix ...
...operations, needed to provide their persistence. Application code may need to contain code to generate persistence-related events, but even these should be automated to the degree possible, for example by monitoring attribute accesses. Transactional storage Data should be stored transactionally with support for rolling back changes. Support for (optional) nested transactions should be anticipated. Effective memory usage Applications should not use undue amo...
Version: None
Released: July 10, 2021
This is a beta preview of Python 3.10 Python 3.10 is still in development. 3.10.0b4 is the fourth and last of the beta release previews. Beta release previews are intended to give the wider community the opportunity to test new features and bug fixes and to prepare their projects to …
...atomic renaming # on POSIX systems, but only gained atomic renaming on Windows in Python # 3.3. A distribution that needs atomic renaming support for reliable # operation might declare the following supported environments. "environment": ["python_version >= '2.6' and sys_platform != 'win32'", "python_version >= '3.3' and sys_platform == 'win32'"] Extension metadata constraints The extension_metadata subfield is a mapping from distribution names to extension metadata snip...
...operations on top of which new techniques can easily be implemented. I started developing MMTK in 1996. I had some experience with mainstream simulation packages for biomolecules that were written in Fortran and had their origins in the 1970s. Those packages were too cumbersome to use and in particular to modify and extend. Since my research work is focused on the development of new simulation techniques, modifiability was a particularly important criterion. Dynamic deformation of the chapero...
...atomic, fast tagging: a cvs tag might take many minutes; a Subversion tag (svn cp) will complete quickly, and atomically. Likewise, branches are very efficient. support for offline diffs, which is useful when creating patches. Moving to python.org SourceForge has kindly provided an important infrastructure for the past years. Unfortunately, the attention that SF received has also caused repeated overload situations in the past, to which the SF operators could not always respond in a timely m...
PEP 312 -- Simple Implicit Lambda PEP:312 Title:Simple Implicit Lambda Author:Roman Suzi <rnd at onego.ru>, Alex Martelli <aleaxit at gmail.com> Status:Deferred Type:Standards Track Created:11-Feb-2003 Python-Version:2.4 Post-History: Contents Abstract Deferral Motivation Rationale Syntax Examples of Use Implementation Discussion Credits References Copyright Abstract This PEP proposes to make argumentless lambda keyword optional in some cases where it is not gra...
...operations of the language. Its syntax is: primary ::= atom | attributeref | subscription | slicing | call See Python Documentation [12] and Grammar Updates section of this proposal for details. The key await difference from yield and yield from operators is that await expressions do not require parentheses around them most of the times. Also, yield from allows any expression as its argument, including expressions like yield from a() + b(), that would be parsed as yield from (a() + b()), whi...
...operation, the grammar is changed so that each NAME must consist of two parts: a name and a type declarator, which is exactly one Unicode character. The declarator uniquely specifies the type of the name, and if it occurs on the left hand side of an expression, this type is enforced: an InquisitionError exception is raised if the returned type doesn't match the declared type. [3] Also, function call result types have to be specified. If the result of the call does not have the declared type, an ...
...atomic. In CPython, the Global Interpreter Lock (GIL) already protects dict methods to make changes atomic. Example using a hypothetical dict_get_version(dict) function: >>> d = {} >>> dict_get_version(d) 100 >>> d['key'] = 'value' >>> dict_get_version(d) 101 >>> d['key'] = 'new value' >>> dict_get_version(d) 102 >>> del d['key'] >>> dict_get_version(d) 103 The field is called ma_version_tag, rather than ma_version, to sug...
...operations, by permitting the inclusion of a "given" suite following any simple assignment statement: TARGET = [TARGET2 = ... TARGETN =] EXPR given: SUITE By convention, code in the body of the suite should be oriented solely towards correctly defining the assignment operation carried out in the header line. The header line operation should also be adequately descriptive (e.g. through appropriate choices of variable names) to give a reader a reasonable idea of the purpose of the operation ...
...operations are performed on a closed object, an exception is raised. The truncate method now accepts a position argument and readline accepts a size argument. There were many changes made to the linuxaudiodev module and its test suite; as a result, a short, unexpected audio sample should now play when the regression test is run. Note that this module is named poorly, because it should work correctly on any platform that supports the Open Sound System (OSS). ...
...atomic as possible. There is also the drawback of there not being a necessarily cheap way to create new checkouts beyond a recursive copy of the checkout directory. A DVCS would lead to a workflow more like this: Branch off of a local clone of the master repository. Edit code, committing in atomic pieces. Merge the branch into the mainline, and Push all commits to the master repository. While there are more possible steps, the workflow is much more independent of the master repository than is ...
...operation on that class, and we can override this default behavior in subclasses. We can also use the Visitor pattern to separate actions from data. But this is not sufficient for all situations. For example, a code generator may consume an AST, and have many operations where the generated code needs to vary based not just on the class of a node, but also on the value of some class attributes, like the BinOp example above. The Visitor pattern is insufficiently flexible for this: it can only s...