AsException

Hook implementation that behaves like a thrown exception. It throws Exception right when the Expected with error is initialized.

With this, one can easily change the code behavior between Expected idiom or plain Exceptions.

version(D_Exceptions)

struct AsException {

static immutable

bool enableDefaultConstructor;

static void onErrorSet(auto ref E err);

}

Members

Static functions

onErrorSet void onErrorSet(auto ref E err): Handler for case when empty error is accessed.

Static variables

enableDefaultConstructor bool enableDefaultConstructor;: Default constructor for Expected is disabled. Same with the opAssign, so Expected can be only constructed once and not modified afterwards.

Examples

1 static assert(!isDefaultConstructorEnabled!AsException);
2 static assert(hasOnErrorSet!(AsException, string));
3 
4 auto div(int a, int b) {
5     if (b != 0) return ok!(string, AsException)(a / b);
6     return err!(int, AsException)("oops");
7 }
8 
9 assert(div(10, 2) == 5);
10 assert(collectExceptionMsg!(Unexpected!string)(div(1, 0)) == "oops");

Meta

Source

See Implementation