Let's stop parser Hell

[Timon Gehr]

On 07/10/2012 09:14 PM, Philippe Sigaud wrote:
> Tue, Jul 10, 2012 at 12:41 PM, Roman D. Boiko<rb at d-coding.com>  wrote:
>
>
>> One disadvantage of Packrat parsers I mentioned was problematic error
>> recovery (according to the article from ANTLR website). After some
>> additional research, I found that it is not a critical problem. To find the
>> exact place of error (from parser's perspective, not user's) one only needs
>> to remember the farthest successfully parsed position (among several
>> backtracking attempts) and the reason that it failed.
>
> IIRC, that's what I encoded in Pegged (admittedly limited) error
> reporting: remember the farthest error.
>
>> It is also possible to rerun parsing with some additional heuristics after
>> failing, thus enabling advanced error repair scenarios.
>
> Do people really what error-repairing parsers? I want my parsers to
> tell me something is bad, and, optionally to advance a possible
> repair, but definitely *not* to automatically repair a inferred error
> and continue happily.

FWIW, this is what most HTML parsers are doing.