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...definition is executed. The grammar for function definitions [11] is now: decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE decorators: decorator+ funcdef: [decorators] 'def' NAME parameters ['->' test] ':' suite parameters: '(' [typedargslist] ')' typedargslist: ((tfpdef ['=' test] ',')* ('*' [tname] (',' tname ['=' test])* [',' '**' tname] | '**' tname) | tfpdef ['=' test] (',' tfpdef ['=' test])* [',']) tname: NAME [':' test] tfpdef:...
...GenericGetAttr and (if they have any writable attributes) PyObject_GenericSetAttr in their tp_getattro and tp_setattro slots. (Or, they can leave these NULL, and inherit them from the default base object, if they arrange for an explicit call to PyType_InitDict() for the type before the first instance is created.) In the simplest case, PyObject_GenericGetAttr() does exactly one dictionary lookup: it looks up the attribute name in the type's dictionary (obj->ob_type->tp_dict). Upon succes...
...generic type. This can be especially hard to read when some of the type parameters are themselves generic types. The bracket structure is not visually similar to how function signatures are written. It requires an explicit import, unlike many of the other most common types like list and dict. Possibly as a result, programmers often fail to write complete Callable types. Such untyped or partially-typed callable types do not check the parameter types or return types of the given callable and thus...
...Generic code dealing with iterators/generators instantiated elsewhere should typically not be littered with close calls. The rare case of code that has acquired ownership of and need to properly deal with all of iterators, generators and generators acquiring resources that need timely release, is easily solved: if hasattr(iterator, 'close'): iterator.close() Open Issues Definitive semantics ought to be chosen. Currently Guido favors Exception Semantics. If the generator yields a value ...
...generic case of x <augop> y (or a similar case using the PyNumber_InPlace API functions) the principal object being operated on is x. This differs from normal binary operations, where x and y could be considered co-operating, because unlike in binary operations, the operands in an in-place operation cannot be swapped. However, in-place operations do fall back to normal binary operations when in-place modification is not supported, resulting in the following rules: If the left-hand objec...
...definition autoconf hash function selection Python API addition sys module Necessary modifications to C code _Py_HashBytes() (Objects/object.c) bytes_hash() (Objects/bytesobject.c) memory_hash() (Objects/memoryobject.c) unicode_hash() (Objects/unicodeobject.c) generic_hash() (Modules/_datetimemodule.c) Performance Hash value distribution Typical length Grand Unified Python Benchmark Suite Backwards Compatibility Alternative counter measures against hash collision DoS Discussion Pluggable...
...generic Docstring Processing System (DPS) framework, which separates out the components (program and conceptual), enabling the resolution of individual issues either through consensus (one solution) or through divergence (many). It promotes standard interfaces which will allow a variety of plug-in components (input context readers, markup parsers, and output format writers) to be used. The concepts of a DPS framework are presented independently of implementation details. Road Map to the Docstr...
...definition 'raw-unicode-escape': See Unicode Constructors for a definition 'native': Dump of the Internal Format used by Python Common aliases should also be provided per default, e.g. 'latin-1' for 'iso-8859-1'. Note: 'utf-16' should be implemented by using and requiring byte order marks (BOM) for file input/output. All other encodings such as the CJK ones to support Asian scripts should be implemented in separate packages which do not get included in the core Python distribution a...
...definition. Once you have the module, call PyModule_GetState to get the state: PyObject *module = PyType_GetModuleByDef(Py_TYPE(self), &module_def); my_struct *state = (my_struct*)PyModule_GetState(module); if (state === NULL) { return NULL; } PyType_GetModuleByDef works by searching the MRO (i.e. all superclasses) for the first superclass that has a corresponding module. Note In very exotic cases (inheritance chains spanning multiple modules created from the same definition), PyType_...
...Generic, TypeVar T = TypeVar('T') class Box(Generic[T]): def __init__(self, content): self.content: T = content Annotating expressions The target of the annotation can be any valid single assignment target, at least syntactically (it is up to the type checker what to do with this): class Cls: pass c = Cls() c.x: int = 0 # Annotates c.x with int. c.y: int # Annotates c.y with int. d = {} d['a']: int = 0 # Annotates d['a'] with int. d['b']: int # Annotates d['b']...
...Definition lists are written like this: what Definition lists associate a term with a definition. how The term is a one-line phrase, and the definition is one or more paragraphs or body elements, indented relative to the term. Tables Simple tables are easy and compact: ===== ===== ======= A B A and B ===== ===== ======= False False False True False False False True False True True True ===== ===== ======= There must be at least two columns in a ...
...Generic Implementation Details - Goodger I'll discuss these together. I believe David Goodger is doing good work, and I still see frequent posts by him in the doc-sig. But I haven't been following this work at all. Since this doesn't affect the language, just a convention, I'm not particularly concerned about this. PEP 262 - Database of Installed Python Packages - Kuchling I think this was a distutils Py-in-the-sky project? Maybe someone should just implement this; I have no ...
...definitions or iterable unpacking. In all these cases, we find that the syntax for sending and that for receiving 'data' are virtually identical. Assignment targets such as variables, attributes and subscripts: foo.bar[2] = foo.bar[3]; Function definitions: a function defined with def foo(x, y, z=6) is called as, e.g., foo(123, y=45), where the actual arguments provided at the call site are matched against the formal parameters at the definition site; Iterable unpacking: a, b = b, a or [a, b] ...
...generic classes in the typing module, as well as with builtin generic classes in the recently accepted PEP 585, because they prohibit isinstance checks. To clarify, generic classes are not prohibited in general from participating in pattern matching, just that their type parameters can't be explicitly specified. It is still fine if sub-patterns or literals bind the type variables. For example: from typing import Generic, TypeVar, Union T = TypeVar('T') class Result(Generic[T]): first: T ...
...definition of impact, it means that any single file for this project may no longer be visible by default, however that file could be years old, or it could be a binary file while there is a sdist available on PyPI. This means that the real impact will likely be much smaller, but in an attempt not to miscount we take the broadest possible definition. At the time of this writing there are 65,232 projects hosted on PyPI and of those, 59 of them rely on external files that are safely hosted outside ...
...generics: def function(value: MyType[T=int]): In some domain, such as computational physics and chemistry, the use of a notation such as Basis[Z=5] is a Domain Specific Language notation to represent a level of accuracy: >>> low_accuracy_energy = computeEnergy(molecule, BasisSet[Z=3]) Pandas currently uses a notation such as: >>> df[df['x'] == 1] which could be replaced with df[x=1]. xarray has named dimensions. Currently these are handled with functions .isel: >&g...
...definitions allow the power and flexibility of block-level directives to be shared by inline text. For example: The |biohazard| symbol must be used on containers used to dispose of medical waste. .. |biohazard| image:: biohazard.png Section structure markup. Section headers in reStructuredText use adornment via underlines (and possibly overlines) rather than indentation. For example: This is a Section Title ======================= This is a Subsection Title -------------------------- Th...
...Definitions for built-in types Non-definition of matrix power Rejected alternatives to adding a new operator Discussions of this PEP References Copyright Abstract This PEP proposes a new binary operator to be used for matrix multiplication, called @. (Mnemonic: @ is * for mATrices.) Specification A new binary operator is added to the Python language, together with the corresponding in-place version: Op Precedence/associativity Methods @ Same as * __matmul__, __rmatmul__ @= n/a...
...generic message shown above. New build-time configuration options While both of the above behaviours would be enabled by default, they would also have new associated configuration options and preprocessor definitions for the benefit of redistributors that want to override those default settings. The locale coercion behaviour would be controlled by the flag --with[out]-c-locale-coercion, which would set the PY_COERCE_C_LOCALE preprocessor definition. The locale warning behaviour would be contro...
...definitions with two blank lines. Method definitions inside a class are surrounded by a single blank line. Extra blank lines may be used (sparingly) to separate groups of related functions. Blank lines may be omitted between a bunch of related one-liners (e.g. a set of dummy implementations). Use blank lines in functions, sparingly, to indicate logical sections. Python accepts the control-L (i.e. ^L) form feed character as whitespace; Many tools treat these characters as page separators, so you...