On Sunday, 22 March 2020 at 18:48:32 UTC, Abby wrote:
Is there a way to create a template that would do the same is
glib
g_return_val_if_fail()
(https://developer.gnome.org/glib/stable/glib-Warnings-and-Assertions.html#g-return-val-if-fail)
I was hoping something like this would work
template returnValIfFail(alias expr, alias val)
{
if(expr) return val;
}
The documentation for the function reads:
"If expr evaluates to FALSE, the current function should be
considered to have undefined behaviour (a programmer error). The
only correct solution to such an error is to change the module
that is calling the current function, so that it avoids this
incorrect call."
Looks like the best approach in D would be to return val when
expr is true and assert(0) otherwise. Also, you'll probably want
the args to be available at runtime, else it would be a very
restrictive template. Perhaps something like this?
```
T returnValIfFail(T)(bool expr, T val) {
if(expr) return val;
else assert(0);
}
void main() {
import std.stdio : writeln;
int y = 10;
int x = returnValIfFail(y >= 10, 20);
writeln(x);
}
```
