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...constructor, Message.add_payload(), Utils.dump_address_pair(), Utils.decode(), Utils.encode() New deprecations: Generator.__call__(), Message.get_type(), Message.get_main_type(), Message.get_subtype(), the 'strict' argument to the Parser constructor. These will be removed in email 3.1. Support for Python earlier than 2.3 has been removed (see PEP 291). All defect classes have been renamed to end in 'Defect'. Some FeedParser fixes; also a MultipartInvariantViolationDefect will be added to messag...
...constructor would ignore all arguments. This is changed now: the constructor refuses arguments in this case. This might break code that worked under Python 2.2. The simplest fix is to add a no-op __init__: def __init__(self, *args, **kw): pass. Through a bytecode optimizer bug (and I bet you didn't even know Python had a bytecode optimizer :-), "unsigned" hex/oct constants with a leading minus sign would come out with the wrong sign. ("Unsigned" hex/oct constants are those...
...constructors for int and boolean arguments. The bool type can be used to select the boolean variant. (The same is apparently the case for some COM interfaces.) The standard bool type can also serve as a way to force a value to be interpreted as a Boolean, which can be used to normalize Boolean values. When a Boolean value needs to be normalized to one of two values, bool(x) is much clearer than "not not x" and much more concise than if x: return 1 else: return 0 Here are some argume...
...constructor functions that allocate (in this case) a stmt_ty struct with the appropriate initialization. The 'kind' field specifies which component of the union is initialized. The FunctionDef() constructor function sets 'kind' to FunctionDef_kind and initializes the 'name', 'args', 'body', and 'attributes' fields. Memory Management Before discussing the actual implementation of the compiler, a discussion of how memory is handled is in order. To make memory management simple, an arena is us...
...constructor.) GvR. Update (2012-04-15): A new MappingProxyType type was added to the types module of Python 3.3. Abstract Add a new frozendict builtin type. Rationale A frozendict is a read-only mapping: a key cannot be added nor removed, and a key is always mapped to the same value. However, frozendict values can be not hashable. A frozendict is hashable if and only if all values are hashable. Use cases: Immutable global variable like a default configuration. Default value of a function p...
...constructors. In essence, the certificate object in this module could be as abstract as a handle that can be used to locate a specific certificate. Concrete implementations may choose to provide alternative constructors, e.g. to load certificates from HSMs. If a common interface emerges for doing this, this module may be updated to provide a standard constructor for this use-case as well. Concrete implementations should aim to have Certificate objects be hashable if at all possible. This will he...
...constructor for pathlib.PurePath and pathlib.Path will be updated to accept PathLike objects. Both PurePath and Path will continue to not accept bytes path representations, and so if __fspath__() returns bytes it will raise an exception. The path attribute will be removed as this PEP makes it redundant (it has not been included in any released version of Python and so is not a backwards-compatibility concern). C API The C API will gain an equivalent function to os.fspath(): /* Return the ...
...constructors that weren't marked as "safe for unpickling" by either having an attribute __safe_for_unpickling__ set to 1, or by being registered in a global registry, copy_reg.safe_constructors. This feature gives a false sense of security: nobody has ever done the necessary, extensive, code audit to prove that unpickling untrusted pickles cannot invoke unwanted code, and in fact bugs in the Python 2.2 pickle.py module make it easy to circumvent these security measures. We firmly believe that, o...
...declaration is not required and structural subtyping is verified statically. For example: interface LabeledItem { label: string; size?: int; } function printLabel(obj: LabeledItem) { console.log(obj.label); } let myObj = {size: 10, label: "Size 10 Object"}; printLabel(myObj); Note that optional interface members are supported. Also, TypeScript prohibits redundant members in implementations. While the idea of optional members looks interesting, it would complicate this proposal an...
...constructor typing.TypedDict to support the use case where a dictionary object has a specific set of string keys, each with a value of a specific type. Here is an example where PEP 484 doesn't allow us to annotate satisfactorily: movie = {'name': 'Blade Runner', 'year': 1982} This PEP proposes the addition of a new type constructor, called TypedDict, to allow the type of movie to be represented precisely: from typing import TypedDict class Movie(TypedDict): name: str year: i...
...constructor argument. Even though YAPPS supports definition of tokens in the grammar, we have not used this capability in XPath, since we have provided my own scanner class. The YAPPS parser will only require a token() method from the scanner object, which must return a four-tuple (start, end, token type, token value). In case of a syntax error, the generated parser will raise a yappsrt.SyntaxError exception. This exception will take the current position and an error message. En...
...constructor do not necessarily specify the attributes or fields of the objects. Moreover, there is no longer a strict ordering of an object's fields and some of the fields might be private and thus inaccessible. And on top of this, the given object might actually be an instance of a subclass with slightly different structure. To address this challenge, patterns became increasingly independent of the original tuple constructors. In a pattern like Node(left, right), Node is no longer a passive ...
...constructors, and those parameters can be positional and may use other names. init is an optional bool parameter that indicates whether the field should be included in the synthesized __init__ method. If unspecified, init defaults to True. Field descriptor functions can use overloads that implicitly specify the value of init using a literal bool value type (Literal[False] or Literal[True]). default is an optional parameter that provides the default value for the field. default_factory is an opt...
...constructor signature would unnecessarily constrain custom container types, for example Patricia trees or gdbm files. Defining a specific string representation for a collection is similarly left up to individual implementations. Note: There are no ABCs for ordering operations (__lt__, __le__, __ge__, __gt__). Defining these in a base class (abstract or not) runs into problems with the accepted type for the second operand. For example, if class Ordering defined __lt__, one would assume that fo...
...declarations. It is illegal to assign to the name __debug__, which is set when the interpreter starts. It is effectively a compile-time constant. A warning will be issued if a global statement for a variable follows a use or assignment of that variable. Standard library unittest.py, a unit testing framework by Steve Purcell (PyUNIT, inspired by JUnit), is now part of the standard library. You now have a choice of two testing frameworks: unittest requires you to write testcases as separate co...
...constructors, which may not bear much resemblance to the resulting instance attributes at all. The second change is intended to make it easier to use pattern matching for the "ducktyping" style checks that are already common in Python. The concrete syntax proposal for these patterns then arose from viewing instances as mappings of attribute names to values, and combining the attribute lookup syntax (.ATTR), with the mapping pattern syntax {KEY: PATTERN} to give cls{.ATTR: PATTERN}. Allowing cls{...