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Diffstat (limited to 'Doc/library/ast.rst')
| -rw-r--r-- | Doc/library/ast.rst | 68 |
1 files changed, 31 insertions, 37 deletions
diff --git a/Doc/library/ast.rst b/Doc/library/ast.rst index a11f8b9..45f16c1 100644 --- a/Doc/library/ast.rst +++ b/Doc/library/ast.rst @@ -120,13 +120,26 @@ Node classes Class :class:`ast.Constant` is now used for all constants. +.. versionchanged:: 3.9 + + Simple indices are represented by their value, extended slices are + represented as tuples. + .. deprecated:: 3.8 Old classes :class:`ast.Num`, :class:`ast.Str`, :class:`ast.Bytes`, :class:`ast.NameConstant` and :class:`ast.Ellipsis` are still available, - but they will be removed in future Python releases. In the meanwhile, + but they will be removed in future Python releases. In the meantime, instantiating them will return an instance of a different class. +.. deprecated:: 3.9 + + Old classes :class:`ast.Index` and :class:`ast.ExtSlice` are still + available, but they will be removed in future Python releases. + In the meantime, instantiating them will return an instance of + a different class. + + Literals ^^^^^^^^ @@ -552,30 +565,33 @@ Subscripting .. class:: Subscript(value, slice, ctx) - A subscript, such as ``l[1]``. ``value`` is the object, often a - :class:`Name`. ``slice`` is one of :class:`Index`, :class:`Slice` or - :class:`ExtSlice`. ``ctx`` is :class:`Load`, :class:`Store` or :class:`Del` + A subscript, such as ``l[1]``. ``value`` is the subscripted object + (usually sequence or mapping). ``slice`` is an index, slice or key. + It can be a :class:`Tuple` and contain a :class:`Slice`. + ``ctx`` is :class:`Load`, :class:`Store` or :class:`Del` according to the action performed with the subscript. - -.. class:: Index(value) - - Simple subscripting with a single value - .. doctest:: - >>> print(ast.dump(ast.parse('l[1]', mode='eval'), indent=4)) + >>> print(ast.dump(ast.parse('l[1:2, 3]', mode='eval'), indent=4)) Expression( body=Subscript( value=Name(id='l', ctx=Load()), - slice=Index( - value=Constant(value=1)), + slice=Tuple( + elts=[ + Slice( + lower=Constant(value=1), + upper=Constant(value=2)), + Constant(value=3)], + ctx=Load()), ctx=Load())) .. class:: Slice(lower, upper, step) - Regular slicing (on the form x:y). + Regular slicing (on the form ``lower:upper`` or ``lower:upper:step``). + Can occur only inside the *slice* field of :class:`Subscript`, either + directly or as an element of :class:`Tuple`. .. doctest:: @@ -589,27 +605,6 @@ Subscripting ctx=Load())) -.. class:: ExtSlice(dims) - - Advanced slicing. ``dims`` holds a list of :class:`Slice` and - :class:`Index` nodes - - .. doctest:: - - >>> print(ast.dump(ast.parse('l[1:2, 3]', mode='eval'), indent=4)) - Expression( - body=Subscript( - value=Name(id='l', ctx=Load()), - slice=ExtSlice( - dims=[ - Slice( - lower=Constant(value=1), - upper=Constant(value=2)), - Index( - value=Constant(value=3))]), - ctx=Load())) - - Comprehensions ~~~~~~~~~~~~~~ @@ -823,8 +818,7 @@ Statements AnnAssign( target=Subscript( value=Name(id='a', ctx=Load()), - slice=Index( - value=Constant(value=1)), + slice=Constant(value=1), ctx=Store()), annotation=Name(id='int', ctx=Load()), simple=0)], @@ -1708,7 +1702,7 @@ and classes for traversing abstract syntax trees: def visit_Name(self, node): return Subscript( value=Name(id='data', ctx=Load()), - slice=Index(value=Constant(value=node.id)), + slice=Constant(value=node.id), ctx=node.ctx ), node) |