NSExpression distanceToLocation:fromLocation:

distanceToLocationfromLocation.m

    expression = [NSExpression expressionForFunction:@"distanceToLocation:fromLocation:" 
                    arguments:@[
                                [NSExpression expressionForConstantValue:to ], 
                                [NSExpression expressionForConstantValue:from ] 
                                ]
                ];
    result = (NSNumber *)[expression expressionValueWithObject:nil context:nil];