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From: David Abrahams (dave_at_[hidden])
Date: 2003-07-12 15:17:08

David Abrahams <dave_at_[hidden]> writes:

>> That's fine with me - that requirement was a source of bugs in my
>> code and violated the rule of least astonishment as far as I was
>> concerned.
>> But before I remove the test from the filesystem library that verifies
>> the old input iterator semantics for directory_iterator, I'd like to
>> verify that the omission of *r++ was a design decision rather than an
>> oversight.
>> The omission of special requirements for *r++ means that Readable and
>> Single Pass = Input, as shown in the diagram, is not actually correct,
>> unless I'm missing something. Thus perhaps it should be discussed in
>> the paper.
> A single-pass iterator is required to support r++ (inherited from the
> incrementable iterator requirements), but I guess that we've
> unintentionally dropped the requiremnt for *r++ of readable
> single-pass iterator, by allowing incrementable iterators to return
> any type convertible to const X&. I think it should require that the
> return type be X, the Assertion/Note/Precondition/Postcondition column
> should be labelled "Operational Semantics" and the lower right entry
> should be moved to the middle column. The same goes for the
> lower-right entry of each of the following two tables.
> I'm going to make those changes; if there are objections, please let
> me know ASAP.


Dave Abrahams
Boost Consulting

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