Question

I have a function that return [[]], and I want to test the result as unit test.
But I found that the expression [[]] == [[]] return false.
Here a simple test code:

# [[]] == [[]];;
- : bool = false

Can someone explain me why this expression is evaluated as false?

Thanks.

Answer 1

Use = since you have structural equality for comparing two values:

# [[]] = [[]];;
- : bool = true

Because == is reference equality, it only returns true if you refer to the same memory location:

let a = [[]]
let b = a

# b == a;;
- : bool = true