<?hh
final class AssertException extends Exception {}
final class Assert {
public static function isNum(mixed $x): num {
if (is_float($x)) {
return $x;
} else if (is_int($x)) {
return $x;
}
throw new AssertException('Expected an int or float value');
}
public static function isInt(mixed $x): int {
if (is_int($x)) {
return $x;
}
throw new AssertException('Expected an int');
}
public static function isFloat(mixed $x): float {
if (is_float($x)) {
return $x;
}
throw new AssertException('Expected a float');
}
public static function isString(mixed $x): string {
if (is_string($x)) {
return $x;
}
throw new AssertException('Expected a string');
}
public static function isArrayOf<T>(
(function(mixed): T) $fn,
mixed $x,
): array<T> {
if (is_array($x)) {
return array_map($fn, $x);
}
throw new AssertException('Expected an array');
}
}