This page is part of the web mail archives of SRFI 0 from before July 7th, 2015. The new archives for SRFI 0 contain all messages, not just those from before July 7th, 2015.
> I guess that answers my question -- any management of conflicting SRFIs is > to be outside the SRFI mechanism itself (or at least SRFI-0). > > I appreciate and agree with your goals for a simple `if-implements'. > However, I am have some remaining concerns. I wouldn't want a user to > have to try a bunch of different command-line options to get a program to > load! > > Perhaps this is the solution: > > Would a reasonable SRFI, in your view, specify a "program-suggests" > special form whose effect is to communicate to the Scheme system that the > program is going to test for some features (SRFIs) and would very much > like to have them available if possible. The implementation is free to > ignore the suggestions if it so chooses. > > e.g., > > (program-suggests SRFI-1) > > (if-implements SRFI-1 > 'cool > (error "you lose -- go get a real Scheme system :-)")) > > ... blah blah blah using SRFI-1 features .. I'm not fond of this idea. Once again the problem is binding time... when does the suggestion of the (program-suggests SRFI-1) take effect? If the compiler can satisfy the suggestion, which branch is chosen in (if-implements SRFI-1 A B) if 1) the form (if-implements SRFI-1 A B) is after (program-suggests SRFI-1) 2) the form (if-implements SRFI-1 A B) is before (program-suggests SRFI-1) 3) the form (if-implements SRFI-1 A B) is in another module I don't see any good answers... and because there are so many variations possible I suggest that such a mechanism be relegated to a separate SRFI. On the other hand I really think that what you want is a module system. In fact I think that the SRFI process should not be used for specifying sets of procedures that could easily form a module (for example SRFI-1). SRFIs should mainly focus on describing basic functionalities that can't be implemented portably and that have to be part of the Scheme system itself. Things like: modules, exceptions, records, IEEE floating point, Unicode, binary I/O, etc. Marc