Errors

Error Handling

return_type identifier(parameter) error_type {

}

• This syntax allows us to return an error code on failure.
• In this case, the return_type and error_type will be wrapped in an union behind the scene, which means only one block of memory will be allocated.
• error_type must be defined using enum type
• error_type is optional, however compiler will enforce checking if used
• One function can have only one unique error_type enum.
• Attempting to return a value that does not match the function's declared return_type or any of its error_type will result in compilation error.

Example:

enum MathError {
  DivideByZero,
  LogZero,
  LogNegativeNumber,
  # ...
}

float divide(float a, float b) MathError {
  
  if(b == 0) 
    return MathError.DivideByZero;
  
  return a / b;
} 

int main(){

  float result1 = divide(12, 3) otherwise (MathError error){
    print(error.name);
  }


  float result2 = divide(12, 3) otherwise (error){  # <- MathError type specification is optional
    if(error = MathError.DivideByZero){
      print("cannot divide by zero\n");
    } 
  }

  return 0;
}