Is "let x = 3;;" an expression?

People say everything in ocaml is an expression and has a type. But how can I understand a statement like

let x = 3;

and

let y = x * x;

These do not look like expressions, right?

>Solution :

OCaml expression are presented here https://v2.ocaml.org/manual/expr.html, and what you have typed is not expressions but let-bindings.

Beware, a single ; is used to separate expressions and is typically used with imperative expressions.

Don’t confuse with ;;