(I'm not sure which mailing list to post this to, so I'm using guile-user as seemingly the most general.)
As an R6RS implementation, it would improve interoperability if Guile accepted .sls and .guile.sls as extensions for module files. In this way, it would be possible to release portable code with wrapper files making it into a module for various R6RS or indeed non-R6RS Schemes. Though these extensions are not dictated by the R6RS itself, they are very widely adopted conventions among R6RS implementations. In general, a foo.sls file is expected to contain a portable R6RS library, whereas a foo.<impl>.sls file wlil contain an R6RS library that uses <impl>-specific features. The Right Thing is probably to simply add them to the primitive-load function, which currently searches only for files named foo.scm and foo. I see no need to insist that foo.sls or foo.guile.sls contain only R6RS library forms as opposed to Guile modules.
