On 12/04/2015 07:53 AM, John Cowan wrote:

> But "string" already means something in Scheme: a *mutable* sequence
> of characters addressable by indexes (such that adding 1 to the index
> gets the next character and subtracting 1 gets the previous character
> modulo boundary cases).

Not in R7RS: "Strings are sequences of characters."
String may be immutable or mutable.  So we already have two kinds
of strings.

> However, I don't see how you can avoid having separate functions
> (or polymorphic functions such that cursors cannot be exact integers)
> for the other span operations, which means that instead of span-ref or
> istring-ref, you have string-ref/cursors: is that really an improvement?

The SRFI-130 draft says that that (span-ref k) returns the k'th character
of span, where k is an exact integer (not a cursor) - just like string-ref.
So no need for a new name.

Likewise with many of the other functions.

For functions that have cursor arguments or results, then I agree we need
a distinguishing name.  But those appear to be in the minority.
Using string-cursor- as a prefix seems reasonable, since that is
already used.
--
	--Per Bothner
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