2 ms·

Hmm, yes. Depends on whether /u/hencq asked about why rec is needed, or why and is needed. I answered above, why rec. And you answered why an explicit groupin

• hencq 12y ago
  Ah very interesting. I guess my question was mainly about and, though I hadn't thought about the reasons for rec. It makes sense that that removes a class of errors. So as a follow-up question: why is type inference impossible without and or what is it about and that makes it possible? For instance, what would happen if I (out of laziness or something) would just insert and everywhere, even for functions that aren't mutually recursive. So, e.g. let rec f x = x + 1 and g y = y * 2 Would type inference somehow fail on that? If not, what's stopping me from writing a version of OCaml where all top level lets are automatically converted to let ... and ... and? (Other than a complete lack of necessary compiler writing skills obviously)
  • sampo 12y ago
    Here is a Stackoverflow answer: http://stackoverflow.com/a/904715/1115446 http://stackoverflow.com/a/904715/1115446 I don't think anything stops you from defining all functions in a program in one giant let rec ... and ..., but doing that might set some other limitations on how you can structure your code.