Lines Matching refs:repeatedly
22 repeatedlycessible through the notation\n""self.name"", and an instance variable hides a class variable with\nthe same name when accessed in this way. Class variables can be used\nas defaults for instance variables, but using mutable values there can\nlead to unexpected results. For *new-style class*es, descriptors can\nbe used to create instance variables with different implementation\ndetails.\n\nClass definitions, like function definitions, may be wrapped by one or\nmore *decorator* expressions. The evaluation rules for the decorator\nexpressions are the same as for functions. The result must be a class\nobject, which is then bound to the class name.\n\n-[ Footnotes ]-\n\n[1] The exception is propagated to the invocation stack unless\n there is a "finally" clause which happens to raise another\n exception. That new exception causes the old one to be lost.\n\n[2] Currently, control "flows off the end" except in the case of\n an exception or the execution of a "return", "continue", or\n "break" statement.\n\n[3] A string literal appearing as the first statement in the\n function body is transformed into the function\'s "__doc__"\n attribute and therefore the function\'s *docstring*.\n\n[4] A string literal appearing as the first statement in the class\n body is transformed into the namespace\'s "__doc__" item and\n therefore the class\'s *docstring*.\n',
45 repeatedly.\n\nTo understand how step (1) occurs, one must first understand how\nPython handles hierarchical naming of modules. To help organize\nmodules and provide a hierarchy in naming, Python has a concept of\npackages. A package can contain other packages and modules while\nmodules cannot contain other modules or packages. From a file system\nperspective, packages are directories and modules are files.\n\nOnce the name of the module is known (unless otherwise specified, the\nterm "module" will refer to both packages and modules), searching for\nthe module or package can begin. The first place checked is\n"sys.modules", the cache of all modules that have been imported\npreviously. If the module is found there then it is used in step (2)\nof import.\n\nIf the module is not found in the cache, then "sys.meta_path" is\nsearched (the specification for "sys.meta_path" can be found in **PEP\n302**). The object is a list of *finder* objects which are queried in\norder as to whether they know how to load the module by calling their\n"find_module()" method with the name of the module. If the module\nhappens to be contained within a package (as denoted by the existence\nof a dot in the name), then a second argument to "find_module()" is\ngiven as the value of the "__path__" attribute from the parent package\n(everything up to the last dot in the name of the module being\nimported). If a finder can find the module it returns a *loader*\n(discussed later) or returns "None".\n\nIf none of the finders on "sys.meta_path" are able to find the module\nthen some implicitly defined finders are queried. Implementations of\nPython vary in what implicit meta path finders are defined. The one\nthey all do define, though, is one that handles "sys.path_hooks",\n"sys.path_importer_cache", and "sys.path".\n\nThe implicit finder searches for the requested module in the "paths"\nspecified in one of two places ("paths" do not have to be file system\npaths). If the module being imported is supposed to be contained\nwithin a package then the second argument passed to "find_module()",\n"__path__" on the parent package, is used as the source of paths. If\nthe module is not contained in a package then "sys.path" is used as\nthe source of paths.\n\nOnce the source of paths is chosen it is iterated over to find a\nfinder that can handle that path. The dict at\n"sys.path_importer_cache" caches finders for paths and is checked for\na finder. If the path does not have a finder cached then\n"sys.path_hooks" is searched by calling each object in the list with a\nsingle argument of the path, returning a finder or raises\n"ImportError". If a finder is returned then it is cached in\n"sys.path_importer_cache" and then used for that path entry. If no\nfinder can be found but the path exists then a value of "None" is\nstored in "sys.path_importer_cache" to signify that an implicit, file-\nbased finder that handles modules stored as individual files should be\nused for that path. If the path does not exist then a finder which\nalways returns "None" is placed in the cache for the path.\n\nIf no finder can find the module then "ImportError" is raised.\nOtherwise some finder returned a loader whose "load_module()" method\nis called with the name of the module to load (see **PEP 302** for the\noriginal definition of loaders). A loader has several responsibilities\nto perform on a module it loads. First, if the module already exists\nin "sys.modules" (a possibility if the loader is called outside of the\nimport machinery) then it is to use that module for initialization and\nnot a new module. But if the module does not exist in "sys.modules"\nthen it is to be added to that dict before initialization begins. If\nan error occurs during loading of the module and it was added to\n"sys.modules" it is to be removed from the dict. If an error occurs\nbut the module was already in "sys.modules" it is left in the dict.\n\nThe loader must set several attributes on the module. "__name__" is to\nbe set to the name of the module. "__file__" is to be the "path" to\nthe file unless the module is built-in (and thus listed in\n"sys.builtin_module_names") in which case the attribute is not set. If\nwhat is being imported is a package then "__path__" is to be set to a\nlist of paths to be searched when looking for modules and packages\ncontained within the package being imported. "__package__" is optional\nbut should be set to the name of package that contains the module or\npackage (the empty string is used for module not contained in a\npackage). "__loader__" is also optional but should be set to the\nloader object that is loading the module.\n\nIf an error occurs during loading then the loader raises "ImportError"\nif some other exception is not already being propagated. Otherwise the\nloader returns the module that was loaded and initialized.\n\nWhen step (1) finishes without raising an exception, step (2) can\nbegin.\n\nThe first form of "import" statement binds the module name in the\nlocal namespace to the module object, and then goes on to import the\nnext identifier, if any. If the module name is followed by "as", the\nname following "as" is used as the local name for the module.\n\nThe "from" form does not bind the module name: it goes through the\nlist of identifiers, looks each one of them up in the module found in\nstep (1), and binds the name in the local namespace to the object thus\nfound. As with the first form of "import", an alternate local name\ncan be supplied by specifying ""as" localname". If a name is not\nfound, "ImportError" is raised. If the list of identifiers is\nreplaced by a star ("\'*\'"), all public names defined in the module are\nbound in the local namespace of the "import" statement..\n\nThe *public names* defined by a module are determined by checking the\nmodule\'s namespace for a variable named "__all__"; if defined, it must\nbe a sequence of strings which are names defined or imported by that\nmodule. The names given in "__all__" are all considered public and\nare required to exist. If "__all__" is not defined, the set of public\nnames includes all names found in the module\'s namespace which do not\nbegin with an underscore character ("\'_\'"). "__all__" should contain\nthe entire public API. It is intended to avoid accidentally exporting\nitems that are not part of the API (such as library modules which were\nimported and used within the module).\n\nThe "from" form with "*" may only occur in a module scope. If the\nwild card form of import --- "import *" --- is used in a function and\nthe function contains or is a nested block with free variables, the\ncompiler will raise a "SyntaxError".\n\nWhen specifying what module to import you do not have to specify the\nabsolute name of the module. When a module or package is contained\nwithin another package it is possible to make a relative import within\nthe same top package without having to mention the package name. By\nusing leading dots in the specified module or package after "from" you\ncan specify how high to traverse up the current package hierarchy\nwithout specifying exact names. One leading dot means the current\npackage where the module making the import exists. Two dots means up\none package level. Three dots is up two levels, etc. So if you execute\n"from . import mod" from a module in the "pkg" package then you will\nend up importing "pkg.mod". If you execute "from ..subpkg2 import mod"\nfrom within "pkg.subpkg1" you will import "pkg.subpkg2.mod". The\nspecification for relative imports is contained within **PEP 328**.\n\n"importlib.import_module()" is provided to support applications that\ndetermine which modules need to be loaded dynamically.\n\n\nFuture statements\n=================\n\nA *future statement* is a directive to the compiler that a particular\nmodule should be compiled using syntax or semantics that will be\navailable in a specified future release of Python. The future\nstatement is intended to ease migration to future versions of Python\nthat introduce incompatible changes to the language. It allows use of\nthe new features on a per-module basis before the release in which the\nfeature becomes standard.\n\n future_statement ::= "from" "__future__" "import" feature ["as" name]\n ("," feature ["as" name])*\n | "from" "__future__" "import" "(" feature ["as" name]\n ("," feature ["as" name])* [","] ")"\n feature ::= identifier\n name ::= identifier\n\nA future statement must appear near the top of the module. The only\nlines that can appear before a future statement are:\n\n* the module docstring (if any),\n\n* comments,\n\n* blank lines, and\n\n* other future statements.\n\nThe features recognized by Python 2.6 are "unicode_literals",\n"print_function", "absolute_import", "division", "generators",\n"nested_scopes" and "with_statement". "generators", "with_statement",\n"nested_scopes" are redundant in Python version 2.6 and above because\nthey are always enabled.\n\nA future statement is recognized and treated specially at compile\ntime: Changes to the semantics of core constructs are often\nimplemented by generating different code. It may even be the case\nthat a new feature introduces new incompatible syntax (such as a new\nreserved word), in which case the compiler may need to parse the\nmodule differently. Such decisions cannot be pushed off until\nruntime.\n\nFor any given release, the compiler knows which feature names have\nbeen defined, and raises a compile-time error if a future statement\ncontains a feature not known to it.\n\nThe direct runtime semantics are the same as for any import statement:\nthere is a standard module "__future__", described later, and it will\nbe imported in the usual way at the time the future statement is\nexecuted.\n\nThe interesting runtime semantics depend on the specific feature\nenabled by the future statement.\n\nNote that there is nothing special about the statement:\n\n import __future__ [as name]\n\nThat is not a future statement; it\'s an ordinary import statement with\nno special semantics or syntax restrictions.\n\nCode compiled by an "exec" statement or calls to the built-in\nfunctions "compile()" and "execfile()" that occur in a module "M"\ncontaining a future statement will, by default, use the new syntax or\nsemantics associated with the future statement. This can, starting\nwith Python 2.2 be controlled by optional arguments to "compile()" ---\nsee the documentation of that function for details.\n\nA future statement typed at an interactive interpreter prompt will\ntake effect for the rest of the interpreter session. If an\ninterpreter is started with the "-i" option, is passed a script name\nto execute, and the script includes a future statement, it will be in\neffect in the interactive session started after the script is\nexecuted.\n\nSee also: **PEP 236** - Back to the __future__\n\n The original proposal for the __future__ mechanism.\n',
78 'while': u'\nThe "while" statement\n*********************\n\nThe "while" statement is used for repeated execution as long as an\nexpression is true:\n\n while_stmt ::= "while" expression ":" suite\n ["else" ":" suite]\n\nThis repeatedly tests the expression and, if it is true, executes the\nfirst suite; if the expression is false (which may be the first time\nit is tested) the suite of the "else" clause, if present, is executed\nand the loop terminates.\n\nA "break" statement executed in the first suite terminates the loop\nwithout executing the "else" clause\'s suite. A "continue" statement\nexecuted in the first suite skips the rest of the suite and goes back\nto testing the expression.\n',
80 repeatedly until it raises an exception.\n\nWhen a "yield" statement is executed, the state of the generator is\nfrozen and the value of "expression_list" is returned to "next()"\'s\ncaller. By "frozen" we mean that all local state is retained,\nincluding the current bindings of local variables, the instruction\npointer, and the internal evaluation stack: enough information is\nsaved so that the next time "next()" is invoked, the function can\nproceed exactly as if the "yield" statement were just another external\ncall.\n\nAs of Python version 2.5, the "yield" statement is now allowed in the\n"try" clause of a "try" ... "finally" construct. If the generator is\nnot resumed before it is finalized (by reaching a zero reference count\nor by being garbage collected), the generator-iterator\'s "close()"\nmethod will be called, allowing any pending "finally" clauses to\nexecute.\n\nFor full details of "yield" semantics, refer to the Yield expressions\nsection.\n\nNote: In Python 2.2, the "yield" statement was only allowed when the\n "generators" feature has been enabled. This "__future__" import\n statement was used to enable the feature:\n\n from __future__ import generators\n\nSee also: **PEP 0255** - Simple Generators\n\n The proposal for adding generators and the "yield" statement to\n Python.\n\n **PEP 0342** - Coroutines via Enhanced Generators\n The proposal that, among other generator enhancements, proposed\n allowing "yield" to appear inside a "try" ... "finally" block.\n'}
