[eatonphil]

Unless Artanis uses FFI calls (which are not part of any SRFI I recall) it is quite reasonable to implement an entire WAF using standard Scheme + SRFIs (for instance, there's an SRFI for socket IO). Build steps always differ but it isn't necessarily difficult to avoid using implementation-specific functionality.

For a non-trivial example, check out the R7RS benchmark suite [0]. 10 of the 30 implementations there complete 95%+ of the benchmarks. (10 is a lot of options...) Racket is probably the most intentionally divergent from Scheme and it still manages to provide an R7RS front-end making it one of only 5 Schemes to finish 100% of the benchmarks (and be pretty fast).

[0] https://github.com/ecraven/r7rs-benchmarks