On Sat, 29 Oct 2005, Alan Watson wrote:

> How is this different from expecting to read a list and getting #f
> instead, and not being sure if the #f appeared as a literal in the input
> stream or was generated by code called by the reader?

It's different because #f is a useful value, not a signal that some
operation failed or was invalid.  In general, operations that are
supposed to retrieve a value can fail, and then what value do they
return?

				Bear