CODEWITHSUNDEEP
ocaml
Pythalex
Pythalex

Reputation: 123

Declaring global variable using local variable

Let's say I want to declare a global variable using local variable : I can do (1)

let y = let x = 1 in x + 1;;

But now if I do (2)

let x = 1 in let y = x + 1;;

It seems ocaml doesn't understand this syntax, it stops at ;;, but I don't see why, because (3)

let x = 1 in 1;;

works, even if it's useless.

What happens at (2) ? How is ocaml trying to analyze this expression ?

Upvotes: 1

Views: 165

Answers (1)

sepp2k
sepp2k

Reputation: 370152

The big difference between the two types of lets is that let ... in ... is an expression, but let without in is not. Now the part after in in let ... in ... must be an expression, so the inless let is not allowed there - it's only allowed at the top-level of a module.

Upvotes: 3

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