Custom Errors in Scilab

In Scilab, we can create custom error handling using structures and functions. Here’s an example that demonstrates a similar concept to custom errors:

// A custom error type
function err = argError(arg, message)
    err = struct('arg', arg, 'message', message);
endfunction

// Function that might return an error
function [result, err] = f(arg)
    if arg == 42 then
        err = argError(arg, "can't work with it");
        result = -1;
    else
        result = arg + 3;
        err = [];
    end
endfunction

// Main function
function main()
    [result, err] = f(42);
    if ~isempty(err) then
        disp(err.arg);
        disp(err.message);
    else
        disp("No error occurred");
    end
endfunction

// Run the main function
main();

In this Scilab example, we’ve created a custom error structure using the argError function. The f function returns both a result and a possible error, similar to the Go example.

The main function demonstrates how to use this custom error handling:

1. We call f(42), which we expect to return an error.
2. We check if an error occurred by checking if err is not empty.
3. If an error occurred, we print the arg and message fields of the error.

When you run this script, it will output:

42
can't work with it

This approach allows for more detailed error information to be passed back to the caller, similar to custom errors in other languages. While Scilab doesn’t have built-in error types like some other languages, this structure-based approach provides a way to create custom error objects with specific fields.

Note that Scilab doesn’t have direct equivalents to concepts like interfaces or method implementations. Instead, we use structures and functions to achieve similar functionality.