D has two features dedicated to error handling: exceptions and assertions. Exceptions are used to handle errors external to the program and assertions are used to verify assumptions inside the program. In other words, assertions are a debugging tool while exceptions handle situations that are beyond your control as a programmer.
Perform the following steps by using assertions and exceptions:
Any time you make an assumption about program state, explicitly express it with
assert.Whenever environmental or user data prevents your function from doing its job, throw an exception.
Write
assert(0);on any branch that you believe ought to be unreachable code.
The code is as follows:
struct MyRange {
int current = 0;
@property bool empty() { return current < 10; }
@property int front() {
// it is a programming error to call front on an emptyrange
// we assume current is valid, so we'll verify withassert.
assert(!empty);
return current...