-----Original Message----- From: David Abrahams [mailto:dave@boost-consulting.com] Sent: Thursday, July 25, 2002 4:00 PM To: Boost-Users@yahoogroups.com Subject: [Boost-Users] Fw: [boost] Iterator Adaptor Poll

Hi Everyone,

Have you tried to use iterator adaptors and found the documentation wanting? I have recently updated the documentation in the CVS: http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/*checkout*/boos t/boost/libs/ utility/iterator_adaptors.htm?rev=HEAD

However, enough people have had problems approaching this library that I thought it would be useful to ask about what would make a gentle introductory example. Beman recently sent me the enclosed, but it seems to define such an oddball toy iterator that I'm not sure it would be a very good motivating example. I'm asking for input, especially from anyone who has "gotten over the hump" so to speak, with iterator adaptors.

I'm brand new to iterator_adaptors, and this is probably way too trivial an example, but I have several classes in my project which aggregate other polymorphic objects in part-whole relationships. I'd like clients who call 'the_aggregate.begin()' to be able to call non-const methods on the aggregate's Parts, but I'd like to prevent direct replacement of the underlying container element 'Part*' itself. Likewise, I'd like clients who call 'the_aggregate.begin() const' to be prevented from doing anything with the aggregate's Parts other than calling it's const methods. Of course, the STL container-supplied iterators aren't intended to work in this way. If this situation is common enough, and iterator_adaptor can be used to quickly generate iterators with the desired behavior (I haven't completely tested it as of yet, but it seems to work), then perhaps this is just one example of a reasonable "Hello, world" introduction to iterator_adaptors. Greg