Requested changes to R4RS

["Jonathan S. Shapiro" <shap@polya.stanford.edu>]

I'll buy into all of their requests, though I would hate to lose the
order isomorphism on char->integer and integer->char.

I think the peek-char debate centered around what peek-char's behavior
was in the face of rubout handlers, which evolved from the discussions
about char-ready?.  The problem is that if we can't define the
semantics for char-ready?, a good argument can be made that for the
same reasons we can't define the semantics of peek-char.  If it was
there to be peeked at, and we can define what that means, then we can
surely define what char-ready? means.

Counterargument is to go the route of redefining streams to have
one-character pushback, but that strikes me as having potentially
undesirable consequences down the road.

Jon Shapiro