CLU's iterators correspond to what [Python] and other
languages call [generators].  CLU iterators were modeled
on Alphard's generators
[http://www.pmg.lcs.mit.edu/CLU.html].

IPL-v generators and [Lisp] mapping functions are related
to Alphard's generators.


Can someone explain the idea of iterator/generator here?

It seems to me that the idea is that rather than explicitly listing an entire range of values (that a variable can take within a loop, etc.) one lists the beginning and ending value of a range plus the incremental factor and the language generates the value as needed.  How is this different than using a for loop though?

An iterator is ''richer'' than a mere index. An iterator carries the ''container'' reference and the element's position with it. You can use 'em without for loops. The iterator controls access to the element.  -- [Todd Coram]

[RS] So would the "loop variable" in a [foreach] come closer to the iterator concept?