preprocessor.itertools_lowering Namespace Reference

Functions
	_bound_names (node)
	_imports (module)
	_itertools_names (module, counts)
	_function (func, names)
	_repeat_operands (call)
	_as_list (call, names)
	_drained (node, counts)
	_drain_once (stmt, name, counts)
	_is_stable (node, rebindable)
	_inline_single_use (block, names, counts, loads, rebindable)
	_blocks (module)
	lower_itertools (module)

Variables
tuple	_FUNCTIONS = ("chain", "repeat")
tuple	_DRAINS = ("list", "tuple", "sorted", "set", "sum", "min", "max")
tuple	_SIMPLE_STATEMENTS = (ast.Assign, ast.AnnAssign, ast.AugAssign, ast.Expr, ast.Assert, ast.Return)
tuple	_LOOPING_SCOPES

Detailed Description

Lower itertools.chain, and itertools.repeat with a count, where a builtin
drains the iterator at once (#8377).

`list(chain(a, b))` becomes `list(list(a) + list(b))` and `sum(repeat(x, n))`
becomes `sum([x] * n)`. A drain runs no code of the program between steps, so
the lazy iterator and the list yield the same elements. A name bound to such a
call and read once, by a drain in the next statement, is replaced there by the
call. Any other use is left as written, which the converter refuses.

Function Documentation

_as_list()

preprocessor.itertools_lowering._as_list ( call, names )

protected

The list expression yielding what `call` iterates, or None.

_blocks()

preprocessor.itertools_lowering._blocks ( module )

protected

_bound_names()

preprocessor.itertools_lowering._bound_names ( node )

protected

_drain_once()

preprocessor.itertools_lowering._drain_once ( stmt, name, counts )

protected

The drain call reading `name` in simple statement `stmt`, run once.

_drained()

preprocessor.itertools_lowering._drained ( node, counts )

protected

The argument a builtin drain call `node` iterates, or None.

_function()

preprocessor.itertools_lowering._function ( func, names )

protected

_imports()

preprocessor.itertools_lowering._imports ( module )

protected

(bound name, function or None for the module) per top-level import
from itertools.

_inline_single_use()

preprocessor.itertools_lowering._inline_single_use ( block, names, counts, loads, rebindable )

protected

_is_stable()

preprocessor.itertools_lowering._is_stable ( node, rebindable )

protected

Whether `node` reads the same value later in the next statement.

_itertools_names()

preprocessor.itertools_lowering._itertools_names ( module, counts )

protected

The names bound once, by a top-level import, to the itertools module
and to its modelled functions.

_repeat_operands()

preprocessor.itertools_lowering._repeat_operands ( call )

protected

lower_itertools()

preprocessor.itertools_lowering.lower_itertools

(

module

)

Lower the drained itertools iterators of `module` to lists.

Variable Documentation

_DRAINS

tuple preprocessor.itertools_lowering._DRAINS = ("list", "tuple", "sorted", "set", "sum", "min", "max")

protected

_FUNCTIONS

tuple preprocessor.itertools_lowering._FUNCTIONS = ("chain", "repeat")

protected

_LOOPING_SCOPES

tuple preprocessor.itertools_lowering._LOOPING_SCOPES

protected

Initial value:

=  (ast.FunctionDef, ast.AsyncFunctionDef, ast.Lambda, ast.ListComp, ast.SetComp,
                   ast.DictComp, ast.GeneratorExp)

_SIMPLE_STATEMENTS

tuple preprocessor.itertools_lowering._SIMPLE_STATEMENTS = (ast.Assign, ast.AnnAssign, ast.AugAssign, ast.Expr, ast.Assert, ast.Return)

protected