Error Handling 5
- The downside of
if try is that it usually puts the main code inside of a block.
- We can instead use
if catch which instead executes on an optional to get the error. And if there is a return from this if then the variable will be considered checked to be a real type.
import std::io;
faultdef DIVISION_BY_ZERO;
fn int? divide_int(int x, int y)
{
if (!y) return DIVISION_BY_ZERO~;
return x / y;
}
fn void main()
{
int a = 4;
int b = 0;
int? x = divide_int(a, b);
// int y = x * 2 this would be an error here
if (catch err = x)
{
// Running if b == 0
io::printfn("Had error: '%s'.", err);
return;
}
// x is a normal "int" now,
// so this works:
int y = x * 2;
}
