Re: lexical list

[R. Kent Dybvig <dyb@iuvax.cs.indiana.edu>]

> >> I think Mark missed the point of my note about the '<datum> syntax.
> 
> Yes I did misunderstand. I didn't realize that the reserved words will
> become unreserved. Is this the current consensus? Is the plan then
> that "syntax" in the current reports will become "standard syntax"
> when macros are added?  What will be the status of top-level syntax
> definitions? The macro committee draft that I saw says that
> define-syntax extends the syntactic environment. I didn't see any
> provision for assignment to a syntactic keyword.

The macro committee is still working out some major issues, and the
only draft so far is very rough and is likely to change substantially
before it goes out.  So, don't make any assumptions based on what you
read there.

To answer the particular question, I believe that it is the concensus
of the macro committee that it should be possible to redefine and
shadow syntactic keywords.  For example, it should be possible to
write:

   (define-syntax quote ???)

or:

   (let ([quote -]) ???)

There has not been any discussion among the macro committee that I am
aware of regarding the status of "'", "`", ",", and ",@", prior to the
current discussion in this newsgroup.  For what it's worth, I don't
like with Pavel's suggestion that "'x" be treated differently "(quote
x)"; this would make the use of "read" as a front end to the compiler
impossible, unless we change "read" in some strange way, and it means
that I can't redefine "quote" and use the handy "'" mark to refer to my
own version of "quote".  It also seems strange to provide a back-door
way to insert top-level "quote" into a program where no such mechanism
is provided for other top-level syntax keywords.

Kent