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Errors in the SRFI documents for SRFI-13 and 14 Martin Grabmueller 03 Apr 2001 16:58 UTC

[I hope these lists are still active]


I am currently doing implementations of SRFI-13 and SRFI-14 for Guile,
and stumbled across errors (at least I think so) in the SRFI document.

Maybe someone here can enlighten me:

1. `char-set-hash'

   The following is stated:

     ``A positive value restricts the return value to the range [0,bound).''

   Below, as example code, there is given:

     (define (char-set-hash cs . maybe-bound) 1)

   which would break if the procedure was called as follows:

     (char-set-hash cs 1)

   because the returned value has to be in [0,1), but 1 is returned.

   `string-hash' and `string-hash-ci' have the same errors.

2. `char-set-unfold' and `char-set-unfold!'

   They are specified as

     char-set-unfold  f p g seed [base-cs] -> char-set
     char-set-unfold! f p g seed base-cs -> char-set

   but the example implementation is given as

     (define (char-set-unfold p f g seed base-cs)
	     (char-set-unfold! p f g seed (char-set-copy base-cs)))

     (define (char-set-unfold! p f g seed base-cs)
	 (let lp ((seed seed) (cs base-cs))
	    (if (p seed) cs                             ; P says we are done.
		(lp (g seed)                            ; Loop on (G SEED).
		(char-set-adjoin! cs (f seed))))))      ; Add (F SEED) to set.

   Note the different order of the predicate and seed mapping procedures.

   [string-unfold is defined correctly]

I wonder if changes to the SRFI document are allowed, if they only
correct errors and not introduce incompatibilities.  If yes, they
should be made.

Best regards,