Line numers & column numbers

[Profpatsch]

I noticed that the parse errors contain neither line numbers nor column numbers (assigning a decoding error to a column).

The first can be easily circumvented by parsing the file line-by-line, and keeping track of which line we are in.
The second is baked into sv, due to the fact how it accumulates errors into a Semigroup of DecodeError;

I think column errors could be added by putting them into BadParse, however they only really make sense if you are parsing line-by-line; however, if you are not doing that, the resulting errors will be pretty useless anyway, because there won’t be any underlying position for BadParses, and you just get a structureless list. I feel like this is a architectural problem with sv though.

[Profpatsch]

My use-case here is to display reasonable human-readable errors for decode problems.

For example, cassava-megaparsec has this feature, it uses a feature of megaparsec to provide decoding errors at the right line numbers: https://hackage.haskell.org/package/cassava-megaparsec-2.0.2/docs/Data-Csv-Parser-Megaparsec.html#t:ConversionError