Re: Optional features in SRFIs Lassi Kortela 24 Jan 2020 18:43 UTC
>> The R7RS version of cond-expand supports (library (foo bar)) >> expressions >> to test for a library that can be imported using (import (foo bar)). >> Would it work in principle to put part of the procedures in a SRFI into >> a separate library, or have I misunderstood how (library ...) works? > Yes, a SRFI can document multiple libraries, and can say that all or > only some are required for conformance, and cond-expand can figure out > what libraries are in fact available and perhaps work around any that > are missing. > > What Scheme programs can't currently do is to reflect at the level of > "Does this library provide this procedure/macro, or not?" That limitation is probably a blessing in disguise. It seems like dubious design if a particular library exports a different set of identifiers depending on environmental conditions.