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Re: SRFI 121: Generators

This page is part of the web mail archives of SRFI 121 from before July 7th, 2015. The new archives for SRFI 121 contain all messages, not just those from before July 7th, 2015.

On 02/06/2015 03:45 PM, John Cowan wrote:
I'd also like close reviews of this SRFI, with particular regard to what
procedures should be excluded or included.  I feel like this proposal is
groping in the dark.

I think formalizing the concept of  generator makes a lot of sense.
However, I'm scared of adding yet another library with dozens of procedures.

I would rather we work to standardize some kind of loop library.  For example,
I like the conceptual elegance of the old Common Lisp "series" library. In that
context one could define a 'scan-generator' or 'generator->series function to
the general loping API, and only need one or two new functions.

The Racket 'for' API has 'in-producer' to handle iterating over a generator.
(Would "producer" be a reasonable alternative name to "gnerator"?)

Generator as the conceptual base of a core looping API may be possible.
However, I have concerns about resource reclamation. For example if you do
(using Racket syntax):
  (for ((x in-producer read-my-file)) ... x ...)
then the overflying my-file doesn't get closed automatically

So I think this API should go on the back-burner, and we should instead
focus on a looping API - keeping generators as part of the latter.
Something based on the Racket for/sequence API would probably work for me
- but then I already have a "sequence" type in Kawa.
	--Per Bothner
per@xxxxxxxxxxx   http://per.bothner.com/