By default, all members in a struct can be accessed. It is possible to make some elements private by prefixing them with _, as in:

struct Foo = { a, _b, c }

# (...)

let foo = Foo(1, 2, 3)

In this case, _b is a private struct member. This means that foo: _b() and foo: _b(666) are valid calls only if made from:

Any call to, say, foo: _b() from another module will yield a NoSuchMethodError exception.

Private struct members also have the following impact: