Concept "lumiera forward iterator"

[ichthyo]

Especially in Proc-Layer we utilise already several iterator implementations. Factor out a concept from these and asure they comply. Integrate with util::for_each and util::isnil. Unit test coverage and documentation in the lumiera DesignProcess

Explanation: the STL defines various and very elaborate iterator concepts. Ichthyo considers most of these an overkill and an outdated aproach. Many modern programming languages build on a very simple iterator concept, which allows once to pull a sequence of values -- and nothing more. Exposing only such an iterator often makes for very clean APIs.

Thus the idea is to formulate a concept in compliance with STL's forward iterator -- but augmented by an stop-iteration test. Of course, there should be some simple support templates to help building compliant iterators. This would give us basic STL integration and look familiar to C++ and Java programmers without compromising the clean APIs.

[ichthyo]

doing some initial steps here, because I need to write yet more iterators...

probably this will stay unfinished for some time to come, because I've more urgent other work...

[ichthyo]

I've now implemented 3 basic templates, which should be enough for now to define the Session interface.

TODO: retrofit the existing iterators, more unit test coverage with real-world use cases, document the iterator concept

[ichthyo]

...so, what remains here to do?

• write a Design-Process entry to document the concept.
• have a look at existing iterators, which could be retrofitted easily
• create tickets for the remaining iterators, to be cleaned up later

The summary of the concept, as it's implemented now, can be found in the doxygen of lib/iter-adapter.hpp

[ichthyo]

Successfully used now within QueryResolver. Cleaned up the back-link in IterAdapter. Wrote a documentation Page to the TiddlyWiki and also used the same text as DesignProcess-Entry