Notice: While JavaScript is not essential for this website, your interaction with the content will be limited. Please turn JavaScript on for the full experience.
...eval loop). Reference Implementation Patch attached to Issue 5251 [1]. That patch uses only existing opcodes (i.e. no SETUP_WITH). Acknowledgements James William Pye both raised the issue and suggested the basic outline of the solution described in this PEP. References [1](1, 2) Issue 5251: contextlib.nested inconsistent with nested with statements (http://bugs.python.org/issue5251) [3]Import-style syntax to reduce indentation of nested with statements (https://mail.python.org/pipe...
Building the PSF: the Q2 2019 Fundraiser Help us raise $60,000 USD by June 30th! #countdown-wrap { width: 70%; padding: 10px; font-family: arial; max-width: 650px; margin: 10px auto 50px; } #goal { font-size: 36px; text-align: center; color: #888; @media only screen and (max-width : 640px) { text-align: center; } } #glass { width: 100%; height: 20px; background: #c7c7c7; border-radius: 10px; float: left; overflow: hidden; } #progress { float: left;...
...eval() (https://docs.python.org/3/library/ast.html#ast.literal_eval) [14]Cargo, Rust's package manager (http://doc.crates.io/) [15]JSON Schema (http://json-schema.org/) [16]Nathaniel J. Smith's file format review (https://gist.github.com/njsmith/78f68204c5d969f8c8bc645ef77d4a8f) Copyright This document has been placed in the public domain. Source: https://github.com/python/peps/blob/master/pep-0518.txt
...eval(), exec - fully support Unicode, and no longer issue a SyntaxError when their input doesn't end with a newline. (New in 2.3a2.) range() - as of 2.3b1 supports long arguments with a magnitude larger than sys.maxint. E.g., range(2**100, 2**101, 2**100) is the following list: [1267650600228229401496703205376L]. dict() - two new features for dict construction: keyword arguments to the dict() constructor are now a shorthand for creating a dictionary from the key/value pairs, and dict.fromkey...
...eval round-trip? OrderedDict([('a', 1), ('b', 2)]) What are the trade-offs of the possible underlying data structures? Keeping a sorted list of keys is fast for all operations except __delitem__() which becomes an O(n) exercise. This data structure leads to very simple code and little wasted space. Keeping a separate dictionary to record insertion sequence numbers makes the code a little bit more complex. All of the basic operations are O(1) but the constant factor is increased for __setite...
...Eval_GetLocals Because PyEval_GetLocals() returns a borrowed reference, it requires the dictionary to be cached on the frame, extending its lifetime and forces memory to be allocated for the frame object on the heap as well. Using PyEval_Locals() will be much more efficient than PyEval_GetLocals(). This code: locals = PyEval_GetLocals(); if (locals == NULL) { goto error_handler; } Py_INCREF(locals); should be replaced with: locals = PyEval_Locals(); if (locals == NULL) { goto error_ha...
...evaluated only once (relevant when A is something like dict[index].attr). However, if A is a mutable object, A may be modified in place. Thus, if A is a number or a string, A += B has the same effect as A = A+B (except A is only evaluated once); but if a is a list, A += B has the same effect as A.extend(B)! Classes and built-in object types can override the new operators in order to implement the in-place behavior; the not-in-place behavior is used automatically as a fallback when a...
...evaluated first. This provides us with the basic spreadsheet model that has proven so valuable for ad-hoc investigation of numerical models. Figure 2. The basic steps Resolver One uses to evaluate cell formulae. Zoom in However, using this method, it is difficult for users to create spreadsheets of any complexity without using cell expressions that are enormous and unwieldy, mixing data, business logic and presentation information. These expressions get duplicated (and almost-duplicated) many...
...eval(), then the result of eval() on it will be used as the default in the Signature.) Ignored if there is no default. required Normally any parameter that has a default value is automatically optional. A parameter that has "required" set will be considered required (non-optional) even if it has a default value. The generated documentation will also not show any default value. Additionally, converters may accept one or more of these optional parameters, on an individual basis: annotation Ex...
...eval loop that would improve performance. Backward Compatibility Ideally this internal-only feature would be completely compatible. However, it does involve a change to refcount semantics in some cases. Only immortal objects are affected, but this includes high-use objects like None, True, and False. Specifically, when an immortal object is involved: code that inspects the refcount will see a really, really large value the new noop behavior may break code that: depends specifically on the ref...
...eval loop binary incompatible changes to the C ABI (although the PEP 384 stable ABI must still be preserved) bug fixes Maintenance releases will also continue as they do today, being strictly limited to bug fixes for the corresponding language release. No new features or radical internal changes are permitted. The new standard library releases will occur in parallel with each maintenance release and will be qualified with a new version identifier documenting the standard library version. Standa...
...eval which silently dropped parts of malformed nodes: >>> from ast import Constant, Dict, literal_eval >>> nasty_dict = Dict(keys=[Constant(None)], values=[]) >>> literal_eval(nasty_dict) # Like eval("{None: }") {} In fact, the author has counted dozens of other call sites in Python's standard library and tooling where it would be appropriate to enable this new feature immediately. Rationale Some critics assert that constant boolean switches are a "code-smell", or...
...eval()'s round trip and "someone who has numeric values representing a Decimal does not need to convert them to a string." The structure will be a tuple of three elements: sign, number and exponent. The sign is 1 or 0, the number is a tuple of decimal digits and the exponent is a signed int or long: Decimal((1, (3, 2, 2, 5), -2)) # for -32.25 Of course, you can construct in this way all special values: Decimal( (0, (0,), 'F') ) # for Infinity Decimal( (0, (0,), 'n') ) #...
...Evaluate the feedback and recommend guidelines for follow-up research or development. As soon as an initial version of the development environment and training material is released to the Python community, the feedback channels will be opened, and the initial feedback will mostly go into improvements of the environment and materials. Later, when more feedback has come in, we will evaluate the use of Python for this project. Maybe Python is perfect; quite possibly changes are nec...
...eval.c . This file will also need a new case statement for the new opcode in the big switch statement in PyEval_EvalFrameEx(). Important Files Parser/ Python.asdl ASDL syntax file asdl.py "An implementation of the Zephyr Abstract Syntax Definition Language." Uses SPARK to parse the ASDL files. asdl_c.py "Generate C code from an ASDL description." Generates Python/Python-ast.c and Include/Python-ast.h . spark.py SPARK parser generator Python/ Python-ast.c Creates C structs co...
...Eval_EvalFrame, PyEval_CallObject, _PyObject_Del, _PyObject_GC_Del, _PyObject_GC_Track, _PyObject_GC_UnTrack PyString_AsEncodedString, PyString_AsDecodedString PyArg_NoArgs, PyArg_GetInt, intargfunc, intintargfunc PyImport_ReloadModule ? 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 313...
...evaluated as: 'abc' + format(expr1, spec1) + format(repr(expr2), spec2) + 'def' + format(expr3) + 'ghi' Expression evaluation The expressions that are extracted from the string are evaluated in the context where the f-string appeared. This means the expression has full access to local and global variables. Any valid Python expression can be used, including function and method calls. Because the f-strings are evaluated where the string appears in the source code, there is no additional expres...
...evaluate the in-place operation). Adding an inline assignment operator Given only the addition of augmented assignment expressions, it would be possible to abuse a symbol like |= as a general purpose assignment operator by defining a Target wrapper type that worked as follows: >>> class Target: ... def __init__(self, value): ... self.value = value ... def __or__(self, other): ... return Target(other) ... >>> x = Target(10) >>> x.value 10 >...
...eval.c. This bug could cause python to crash. It was related to using a 'continue' inside a 'try' block. SF bug #422004: Py_Initialise fix that allows reload(exceptions) to work - this is apparently very important for embedded python working with multiple interpreters. SF patch #500401: webbrowser: tightened up the command passed to os.system() so that arbitrary shell code can't be executed because a bogus URL was passed in. The Python compiler package was updated to correctly calculate stack de...
...Eval_EvalCodeEx 62713 3.3354 python tupledealloc 57071 3.0353 python _PyEval_CallFunction 50009 2.6597 24532.jo #u#force_unicode 47468 2.5246 python PyUnicodeUCS2_Decode 45829 2.4374 python PyFrame_New 45173 2.4025 python lookdict_string 43082 2.2913 python PyType_IsSubtype 39763 2.1148 24532.jo #u#render5 38145 2.0287 python _PyType_Lookup 37643 2.0020 python PyObject_GC_UnTrack 37105 1.9734 python frame_dealloc 36849 1.9598 python PyEval_EvalFrame 35630 1.8950 24532.jo #u#resolve 33313 1.7717 ...