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Cleaned up some of Jeremy's wording. Added a few comments on changes

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from the accepted paper.  Committed Python doc regeneration scripts.


[SVN r21079]
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Dave Abrahams
2003-12-02 13:10:55 +00:00
parent fe52e0d665
commit 593311f43e
4 changed files with 322 additions and 32 deletions
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doc/new-iter-concepts.rst
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@ -299,17 +299,27 @@ given in the following diagram.
Like the old iterator requirements, we provide tags for purposes of
dispatching based on the traversal concepts. The tags are related via
inheritance so that a tag is convertible to another tag if the concept
associated with the first tag is a refinement of the second tag. Our
design reuses ``iterator_traits<Iter>::iterator_category`` as the
access mechanism for the traversal tag. If an iterator wishes to meet
the requirements of both a new iterator concept and an old iterator
concept, it can use an iterator category type that inherits from both
the the old iterator tag and the new traversal tag.
associated with the first tag is a refinement of the second tag.
Our design reuses ``iterator_traits<Iter>::iterator_category`` to
indicate an iterator's traversal capability. To specify
capabilities not captured by any old-style iterator category, an
iterator designer can use an ``iterator_category`` type that is
convertible to both the the most-derived old iterator category tag
which fits, and the appropriate new iterator traversal tag.
.. dwa2003/1/2: Note that we are not *requiring* convertibility to
a new-style traversal tag in order to meet new concepts.
Old-style iterators still fit, after all.
We do not provide tags for the purposes of dispatching based on the
access concepts. There are two reasons: we could not find a way to
automatically infer the right access tags for old-style iterators and
the need for dispatching based on the access concepts is not as great.
access concepts, in part because we could not find a way to
automatically infer the right access tags for old-style iterators.
An iterator's writability may be dependent on the assignability of
its ``value_type`` and there's no known way to detect whether an
arbitrary type is assignable. Fortunately, the need for
dispatching based on access capability is not as great as the need
for dispatching based on traversal capability.
A difficult design decision concerned the ``operator[]``. The direct
approach for specifying ``operator[]`` would have a return type of
@ -373,6 +383,10 @@ member of type ``T``.
| | |to ``(*a).m`` |
+-----------------------------------+------------------------+-------------------------+
.. TR1: the originally-proposed requirement that typeof(*a) == R
was too restrictive. Now we just require that it's
convertible to R and that accessing a T through that conversion
is equivalent to accessing a T directly.
.. _Writable Iterator:
@ -395,8 +409,6 @@ output.
| | | value types of ``X`` |
+-------------------------+--------------+----------------------------+
Swappable Iterators [lib.swappable.iterators]
---------------------------------------------
@ -472,6 +484,8 @@ semantics.
| |``incrementable_traversal_tag``| |
+--------------------------------+-------------------------------+--------------------+
.. TR1: incrementable_iterator_tag changed to
incrementable_traversal_tag for consistency.
Single Pass Iterators [lib.single.pass.iterators]
-------------------------------------------------
@ -502,6 +516,9 @@ semantics.
| |``single_pass_traversal_tag``| |
+--------------------------------+-----------------------------+---------------------------+
.. TR1: single_pass_iterator_tag changed to
single_pass_traversal_tag for consistency
Forward Traversal Iterators [lib.forward.traversal.iterators]
-------------------------------------------------------------
@ -533,6 +550,9 @@ semantics.
| |``forward_traversal_tag`` | |
+---------------------------------------+-----------------------------------+---------------+
.. TR1: forward_traversal_iterator_tag changed to
forward_traversal_tag for consistency
Bidirectional Traversal Iterators [lib.bidirectional.traversal.iterators]
-------------------------------------------------------------------------
@ -570,6 +590,8 @@ the stated semantics.
| | | |
+------------------------------------+---------------------------------------------+---------------------+
.. TR1: bidirectional_traversal_iterator_tag changed to
bidirectional_traversal_tag for consistency
Random Access Traversal Iterators [lib.random.access.traversal.iterators]
-------------------------------------------------------------------------
@ -635,6 +657,8 @@ constant object of type ``Distance``.
| |``random_access_traversal_tag`` | | |
+-------------------------------------------+-------------------------------------------------+-------------------------+----------------------+
.. TR1: random_access_traversal_iterator_tag changed to
random_access_traversal_tag for consistency
Addition to [lib.iterator.synopsis]