Similarity between `module` and `let in / where`.

[AnthonyJacob]

I think that it is possible to think of let in / where as an anonymous module, that is immediately exposed to local scope and vice versa.

Thus one of them can be replaced with the other.

[ptol]

Yes

x = 
  foo = 1
  bar = 2

(foo = 1, bar = 2) is anonymous record but with in

x = 
  foo = 1
  bar = 2
  in
  foo + bar

this record is exposed to foo + bar expression.