05:58 <SrPx> What is the best way to emulate ADTs (sum types) in Racket, using only Scheme primitives (R6RS)? I'm thinking in using a pair with a symbol representing the constructor on the first element, and a tuple of the fields on the second element. But I wonder if there is a more efficient way?

11:03 <bremner> SrPx: afaik the usual approach in racket is to use structs. I'm not sure if records in R6RS would be a suitable substitute (or what SRFI9 brings)

14:59 <SrPx> hmmm

15:28 <SrPx> bremner: I've benchmarked and using a pair with a symbol as the tag, and a vector for the fields, was about 35% faster than records

15:28 <SrPx> is that expected?

15:55 <bremner> dunno. Which records was that, the built-in or srfi9 ? some chatter on stack-overflow suggests the srfi9 ones are better, fwiw

16:43 <SrPx> I see

16:43 <SrPx> I don't know what srfi9 is, I'll check