2017-07-26 7:26 GMT+02:00 Marc Nieper-Wißkirchen <xxxxxx@nieper-wisskirchen.de>:

(lambda (x _ _) something) is parallel to the other use of _ in Scheme, so far, namely the use of _ in syntax-rules patterns. So it makes a lot of sense. On the other hand, the role of _ in (is _ < x) is not the same. In the latter case, the argument corresponding to _ is not neglected. (That's why I wrote in an earlier post that <> is more consistent than _-

I think they are both equally consistent, but the choice of <> is just more wasteful. Maybe I'm missing something, but I believe the convention established in R7RS only concerns the context of binding/patterns, and the suggestion to use _ in the "is" macro concerns the context of expressions/templates, where interpreting "_" as ignoring something simply doesn't make sense (if you use it, you don't ignore it)