Option for the consumer to override the error message?

[mii9000]

I suggest there should be an option for the user of the library to override the error messages of validators.
@afucher What do you think? I can work on it.

[afucher]

Hey @ibrahim-islam , I think that this make sense.
Do you have any proposal about how to do that? I was thinking that this is a behaviour of the validator implementation, but would like to understand if you have any idea.

[mii9000]

@afucher I think a simple optional argument to override the error message when initializing the validator is one option.

[mii9000]

@afucher How does this API look like?

    public abstract class BaseValidator : IValidator
    {
        protected readonly string Pattern;
        protected string ErrorMessage;

        protected BaseValidator(string pattern, string errorMessage)
        {
            Pattern = pattern;
            ErrorMessage = errorMessage;
        }

        public virtual string GetErrorMessage() => ErrorMessage;

        public abstract bool Validate(string value);
    }

    public class RegexValidator : BaseValidator
    {
        public RegexValidator(string pattern)
            : base(pattern, $"Answer should match pattern {pattern}")
        { }

        public override bool Validate(string value) => Regex.IsMatch(value, Pattern);

        public RegexValidator WithErrorMessage(string message)
        {
            ErrorMessage = message;
            return this;
        }
    }

[afucher]

Hey @ibrahim-islam ,
why do we need this abstract class with Pattern ?
Others validators doesn't need this.

[afucher]

Hey @ibrahim-islam ,
what do you think about an approach more Fluent?

Like:

var validator = new RegexValidator("some pattern").WithErrorMessage("My custom error message");