Arthur A. Gleckler scripsit:

> Still, it would be a disservice to provide it in an implementation that
> didn't support tail recursion, for example, since that's a basic feature
> of the language and many programs won't work without it.  It would be
> better to agree on a feature identifier that such languages can support.
> This can be outside the spec, for example in an SRFI.

Mumble.  The point is to specify an intent to conform to R7RS
specifically, as opposed to other Scheme standards.  There is no
standard that doesn't require tail recursion, and there have always
been implementations (well, since 1989 at least) that don't support it
in the general case.

--
The experiences of the past show                John Cowan
that there has always been a discrepancy        cowan@ccil.org
between plans and performance.                  http://www.ccil.org/~cowan
        --Emperor Hirohito, August 1945