[plt-scheme] Re: polymorphism of primitive types

From: David Van Horn (dvanhorn at cs.brandeis.edu)
Date: Tue Oct 18 12:26:29 EDT 2005

Matthias Felleisen wrote:
> I was wrong. R5RS says:
>> library procedure:  (map proc list1 list2 ...) 
>> The lists must be lists, and proc must be a procedure taking as many
>> arguments as there are lists and returning a single value. If more
>> than one list is given, then they must all be the same length.
> So this means you must redefine map for cyclic lists just as you must
> for streams.

Or use SRFI 1.


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.

At least one of the argument lists must be finite:

(map + '(3 1 4 1) (circular-list 1 0)) => (4 1 5 1)

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