Allan J Cooper (4) [Avatar] Offline
Idris *optionally* allows the keyword "implementation" as part of the signature of an implementation of an interface. Imo this is a wonderful idea. I personally find it disorienting/ jarring reading files when the keyword is missing because then the signature "looks different" from other Idris constructs, particularly if you forgot that Eq or Num or FooBar has even ever been defined as an an interface (yes, i can figure it out, but i stumble).

In any case, I personally would find it helpful if Chapter 7 introduces the keyword, optional or not, even with a disclaimer like "we won't be using this optional keyword in the rest of this book (but you may if you want to)".