Update `zip` to accept lists of different lengths?

[usefulmove]

The current implementation of zip does not behave the way it does in Haskell or Python. Haskell and Python accept list of different lengths. This has caught me off guard, and I've had to roll my own. I'm opening this issue to propose an update to zip to accept arguments that are of different lengths. I'd be happy to open a pull request if this behavior is desired.

An example of the proposed behavior:

(zip '(3 1 2) '(0 5)) ; => ((3 0) (1 5))

Let me know what you think.

[filiplajszczak]

Current behavior ( map erroring) for lists of different lengths is not documented and not tested so it could be easily changed.

At the same time proposed behavior means that zip would be dropping data silently. That might be undesired.
That problem could be solved by optional keyword argument that would default to strict equal lists length enforcement, but could be manually set to lax. It maintains backward compatibility by default.

Let's consider that:

> (zip '(3 1 2) '(0 5))
map: all lists must have same size
  first list length: 3
  other list length: 2
  procedure: #<procedure:list>
> (zip '(3 1 2) '(0 5)  #:strict #f)
'((3 0) (1 5))

It could be also other way around with lax being default.
Other possibility is to make strict optional positional argument not keyword.
There could be also two different procedures eg zip and zip-strict or zip and zip-lax.

@codereport What do you think?

[filiplajszczak]

There is another possibility, to add (require srfi/1) and have extended map

This procedure is extended from its R5RS specification to allow the arguments to be of unequal length; it terminates when the shortest list runs out.

See https://docs.racket-lang.org/srfi/srfi-std/srfi-1.html#map

eg.

Welcome to Racket v8.12 [cs].
> (map list '(3 1 2) '(0 5))
map: all lists must have same size
  first list length: 3
  other list length: 2
  procedure: #<procedure:list>
 [,bt for context]
> (require srfi/1)
> (map list '(3 1 2) '(0 5))
'((3 0) (1 5))