How do I get line numbers using pegged?

[Paul Backus]

On Monday, 15 August 2022 at 22:55:30 UTC, TheZipCreator wrote:
> So I've looked at the [pegged 
> library](https://github.com/PhilippeSigaud/Pegged) and used it 
> a little bit and it seems really good. But there doesn't seem 
> like there's a built-in way to get line numbers of nodes in the 
> parse tree (or maybe I'm missing something). This would useful 
> because if an error occurs during interpreting/compiling, you 
> could give the user a line number where their error occurred by 
> just getting the line number of the node that's currently being 
> processed. Is there a way to do this in pegged?

It looks like the parse tree in pegged stores the start and end 
byte indices of the portion of the input text it corresponds to:

https://github.com/PhilippeSigaud/Pegged/blob/v0.4.6/pegged/peg.d#L251-L252

It should be possible to compute line numbers based on these 
indices.