Problems with assert in function definition

[Alexander-Schiendorfer]

Hi,

I would like to add some assertions to a function that returns "array[int,int] of int" (in reality, an adjacency matrix).

function array[int, int] of int: doSomething(array[int, int] of int: edges) =
assert(true,
"This should work",
edges);

output[ "\(doSomething([| 5, 3, 5 | 1, 2, 3 |]))" ];
solve satisfy;

which does not work and returns:

MiniZinc: type error: no function or predicate with this signature found: `assert(bool,string,array[int,int] of int)'

However, when doing the same with just an int, everything's fine:

function int: doSomething(int: e) =
assert(true,
"This should work",
e);

output[ "\(doSomething(5))" ];
solve satisfy;

Is there a workaround?

Cheers,
Alex

[Alexander-Schiendorfer]

For anyone running into a similar issue, here is a (not really pretty) workaround that gets the job done:

function bool: preassert(bool: expr, string: message) = 
assert(expr, message, expr);

function array[int, int] of int: doSomething(array[int, int] of int: edges) =
let {
  bool: cons = preassert(false, "Should be consistent")
} in
if cons then edges else [| |] endif;

output[ "\(doSomething([| 5, 3, 5 | 1, 2, 3 |]))" ];
solve satisfy;