lazy list

[Derek Frost]

Please could someone give a very basic example of a lazy list just to point me in the right direction??

I have done this:

(:.) v l = v :. l; //from the website then this

take 2 (1 :. [2..9]); // which just hangs.  Maybe I misunderstood ??  :)

//many thanks!

[Madis Janson]

On Sun, 4 Jun 2017, Derek Frost wrote:

> Please could someone give a very basic example of a lazy list just to point me in the right direction??
> I have done this:
> (:.) v l = v :. l; //from the website then this

Thus you overrode the :. operator with one that recursively calls itself.
Same as f v l = f v l; because there is no (end) condition, it is endless loop.

The std.yeti module has similar definition - with norec keyword:

norec (:.) v l = v :. l;

The norec means no recursive binding, therefore using compilers inbuilt
:. definition (to provide actual lambda binding).

> take 2 (1 :. [2..9]); // which just hangs.  Maybe I misunderstood ??  :)

Thats the endless recursion of previous :. definition.
Without it a compiler error is given:

1:14: Cannot apply (() -> list?<number>) -> list<number> function to list<number> argument

This is because :. expects lambda generating the tail list as second argument.

> take 2 (1 :. \[2..9])

[1,2] is list<number>

[Derek Frost]

Actually I figured it out but many thanks for responding!!  I really like the yeti, it's just what I was looking for.  I was using ocaml, but I prefer yeti.

Derek.

[Derek Frost]

In your yetiscript pages you say help welcome.  I could translate 'Introduction to Yeti' into French and Esperanto if you're interested??  In 2008 I translated a book by R M Stallman so I've got some experience in translation..  :)

I could also help in other ways but I'm not good at programming, it's just a hobby.

On Sunday, June 4, 2017 at 8:54:06 PM UTC+2, Derek Frost wrote: