1 assert(err("foo").expectErr("oops") == "foo"); 2 version (D_Exceptions) 3 { 4 assert(collectExceptionMsg!Throwable(Expected!int.init.expectErr("oops")) == "oops: empty"); 5 assert(collectExceptionMsg!Throwable(ok(42).expectErr("oops")) == "oops: 42"); 6 assert(collectExceptionMsg!Throwable(ok().expectErr("oops")) == "oops: empty"); // void value 7 } 8 9 assert(ok("foo").expect!(a => "bar") == "foo"); 10 assert(err!string("foo").expect!(a => "bar") == "bar"); 11 assert(err!string("foo").expect!((a) {}) is null); 12 13 assert(ok("foo").expectErr!(a => "bar") == "bar"); 14 assert(err!string("foo").expectErr!(a => "bar") == "foo"); 15 assert(ok!string("foo").expectErr!((a) {}) is null);
Unwraps a result, yielding the content of an error value. If there is none, or success value, it throws assert(0) with the provided message.