Generator wrapper for iterators in nim
Iterators in nim are not easy to handle. Passing the iterator around is not possible with inline-iterators and has some restrictions when using closures. Once started iterators have to run until the end. Try writing a zip function that combines two iterators - it is merely impossible (given that both iterators run undeterminedly).
It is not possible to pause execution and continue - as it is possible in Python. Python also supports getting the next element with a next function.
The generator tries to copy exactly that behavior in Python and wraps the iterator with a Generator type that supports a next and a finish function and also provides its own items-iterator implementation so that it can also be used as an iterator again after passing it around.
The implementation (currently) uses threads - one GeneratorThread for each generator - that feeds the data from the iterator to the main thread where the data can be received item by item.
This is still in early stage - although the general concept is already working. Help is welcome ;-)
- performance test
- more documentation
- zip -> generate tuples (or adapt zero_functional to support that - e.g. iterate until one of the iterators has ended).
- enumerate (as in python = zip with index)
- test with file reading iterator
- forward exceptions (?)