Re: New egg: CHICKEN Transducers

[siiky]

> How about SRFI 42?

I wrote a little bit in #chicken but think it should be added here as well.


Pros of SRFI 42:

+ It's short and clear. It feels very natural to me. Maybe just because 
I've used it for some time while I've just been introduced to 
transducers now, but I have the impression that's not it.

Pros of transducers (the egg):

+ Seems to be more generic: the operation and the resulting data 
structure are decoupled.
+ Seems to be easier to implement/understand (based on the examples of 
the post): look at "Why this whole :dispatched business?" from the SRFI 
42 doc[0] to compare with a `type-fold`, or the sample implementation[1].


There are some things I would still use SRFI 42 for, at least for now 
that I'm new to transducers. For example:

(list-ec (:list x lst1)
         (:list y lst2)
         (if (even? (* x y)))
         (cons x y))

Which is similar to  (filter even (map * lst1 lst2))  but more 
performant because there's no intermediate list. I have no idea how to 
do this with transducers.


[0]: https://srfi.schemers.org/srfi-42/srfi-42.html
[1]: https://srfi.schemers.org/srfi-42/ec.scm