[Haskell-cafe] How did iteratees get their names?

[Henrik Nilsson]

Hi,

Ertugrul wrote:

 > Just like chatter and chattee, employer and employee, there is an
 > iterator (usually as part of an enumerator/ee) and an iteratee.

Thanks for the attempt to explain. But I, at least, remain mystified,
and I agree with Douglas that the terminology is confusing.

Usually, the relationship between word-pairs such as the ones above is
pretty obvious, typically implying some kind of subordinate
relationship. For example:

   * employer: the one employing
     employee: the one employed

   * tutor: the one teaching, instructing, providing care
     tutee: the one receiving instruction, care

   * caller: that which is calling
     callee: that which is being called

And so on.

The above would suggest that "iterator" would be something that
iterates over something, and that "iteratee" would be (an element
of) that being iterated over.

However, no such simple relationship seems to emerge from the
provided explanation.

I also had a look at John Millikin's page on Understanding Iteratees,
which is very good:

    https://john-millikin.com/articles/understanding-iteratees/

But, the intuition that comes across there is:

   * iteratee: a stream (of sorts) consumer

   * enumerator: a stream (of sorts) producer

   * enumeratee: a stream (of sorts) transformer

And "iterator" isn't mentioned at all.

I might be missing something, but the terminology is hardly crystal
clear. Which is a pity!

Best,

/Henrik

-- 
Henrik Nilsson
School of Computer Science
The University of Nottingham
nhn at cs.nott.ac.uk