New draft

[Marc Feeley <feeley@iro.umontreal.ca>]

I have reviewed the comments made on this list and SRFI 88 and have  
come to the conclusion that a parameter list syntax different from  
DSSSL may be a more elegant and acceptable way of extending Scheme to  
support optional and named parameters.  My original proposal based on  
the DSSSL syntax was aimed to ensure that several implementations of  
Scheme would support a compatible approach for optional and named  
parameters.  However, I have polled the implementors of Scheme  
implementations which support a DSSSL-like syntax and most of them  
are willing to consider a cleaner syntax.  My goal is thus achievable  
even if a different syntax is used, as long as most of these Scheme  
implementors adopt it.  The new draft presents an alternate approach  
which could replace the original proposal if there is consensus.  If  
however this new approach is even more controversial I will revert to  
the original DSSSL-like syntax.

Donavan Kolbly assured me that the new draft of SRFI 89 will be  
available on the SRFI web site within a few days.  In the meantime  
you can get it on my web page at:

   http://www.iro.umontreal.ca/~feeley/srfi-89.html

The new syntax does away with the `#!optional', `#!key' and `#!rest'  
markers.  Instead, a syntax that is inspired from EBNF is used to  
denote optional parts (square brackets in the parameter list around  
the optional parameters).  Moreover, to reinforce the similarity  
between the appearance of `defines' and the call site, named  
parameters are specified in the parameter list by giving both the  
keyword and the variable corresponding to that parameter.  Finally,  
the approach now supports required named parameters.  All the details  
are given in the SRFI document.

Marc