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Re: the discussion so far

This page is part of the web mail archives of SRFI 75 from before July 7th, 2015. The new archives for SRFI 75 contain all messages, not just those from before July 7th, 2015.

Thomas Bushnell BSG scripsit:

> When you provide a function that does almost-the-right-thing, you are
> encouraging programmers to use it.  The only case where you have
> identified a value to this function (when implemented as a simple
> radix comparator on codepoints) is when you have binary search trees
> which you want to exchange between scheme systems.

I picked that as a counterexample to the claim that there were no such
use cases.

> Yet, this function will not be used only for that purpose.  Instead,
> it will be used just as the R5RS function is: a general purpose way of
> sorting strings to alphebetize them for human-readable output.  

Then document that it should not be used in that way.

> Any programmer, you see, who wants to write code that Does The Right
> Thing and uses this function, thinking, "oh, this will sort strings
> usefully for human readable output", will be wildly misled.  On their
> scheme system it will be fine, but then on a fancy enough scheme
> system, with full Unicode support, their code will break.
> It would have been better to tell them "Scheme has no portable way to
> sort strings for human-readable output" than to provide a function
> which is almost right.

I quite agree that such a disclaimer is very much in order; I note that
R5RS does not say that the procedures in question *can* be used for such
a purpose, and indeed they cannot reliably be so used.

John Cowan  jcowan@xxxxxxxxxxxxxxxxx  www.reutershealth.com  www.ccil.org/~cowan
The whole of Gaul is quartered into three halves.
        -- Julius Caesar