What exactly is "bigint" in F#?

Question

I understand that bigint is not a function but rather a type constructor. That's why this fails:

// Won't compile
let foo = 10 |> bigint

I understand that I can create a new function which accepts an integer and returns a bigint, and then the pipeline operator will work.

However, I don't understand why this works:

let bar = bigint 10

If bigint is a type constructor, why don't I need new? Where exactly is bigint defined as an alias to System.Numerics.BigInteger's constructor?

Answer 1

bigint is type abberviation for System.Numerics.BigInteger so when you type

let x = bigint 10

you actually create instance of BigInteger. In F# new is optional in constructors, basically it should be used when creating instances of types that implement IDisposable