Custom error messages

[alexeyr]

From documentation, there doesn't seem to be a way to fail with a specified error message (e.g. in test example, I'd like to tell the user only even integers are allowed explicitly). Pergaps an optional argument could be added to mismatch?

[alexander-myltsev]

Good point. I see no easy workaround either. @sirthias do you know any?

[sirthias]

The only way to influence error messages right now is through rule naming. These two commits made that even easier:

• https://github.com/sirthias/parboiled2/commit/e266803f36a0a64109e641fd04a0e21add2c0d3d
• https://github.com/sirthias/parboiled2/commit/814e0641e451591456ff0a9bdd85901a391e6c7f

However, even more flexibility would certainly be good. So I think this is a valid ticket, thanks for raising the issue!

[sirthias]

Superseded by https://github.com/sirthias/parboiled2/issues/125