[r6rs-discuss] [Formal] String positions and string slices

[John Cowan]

Chris Hanson scripsit:

> Given this view, I think that strings should be read-only, and that
> operations like string-length and string-ref are a bad idea.  

I like that idea too, but I wanted to maintain as much backward
compatibility as practical.

> should be pointers into strings that can be used to ask questions like
> "what is the character on my right (or left)?" and "is there a character
> to my left (right)?".  Positions shouldn't be independent of the strings
> they reference, they should instead incorporate those strings.

That eliminates any chance of them being lightweight fixnums.

Bug: I forgot to have an alternative to string-ref that works in
terms of positions.  Please consider that included.

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