[plt-scheme] no mappend! in scheme/mpair?

At Mon, 14 Jan 2008 11:59:22 -0800, John Clements wrote:
> I would think that the principal use of mpairs would be to allow  
> programmers to use existing mutable-pair code, including append! and  
> reverse!.  However, I don't see an mappend! or mreverse!.  Is their  
> omission an oversight, or is there some good reason not to have them?

No good reason. They're missing only because the `scheme/mpair' library
was originally created to support `r5rs'.

Please feel free to add `mappend!' and `mreverse!' and update the docs.

Matthew