Infallible ANSI to HTML conversion

[CosmicHorrorDev]

Currently there are a small handful of scenarios where ansi_to_html::convert() can return an error. Specifically it's

• Error::ParseInt(std::num::ParseIntError) gets returned if there's a number in an ansi code that's outside the 8-bit range e.g. \e[256m
• Error::Invalid { msg: String } which can be returned when
  • A couple of (i think unreachable based on all the call-sites) 4-bit color parsing
    

    to-html/crates/ansi-to-html/src/color.rs

    Lines 25 to 27 in f95215d

    	return Err(Error::InvalidAnsi {
    	msg: format!("unexpected integer {} parsing 4-bit color", code),
    	})

    
    

    to-html/crates/ansi-to-html/src/color.rs

    Lines 43 to 45 in f95215d

    	return Err(Error::InvalidAnsi {
    	msg: format!("unexpected integer {} parsing bright 4-bit color", code),
    	})

  • Or an incorrectly structured 8-bit or RGB ansi sequence
    

    to-html/crates/ansi-to-html/src/color.rs

    Line 63 in f95215d

    .ok_or_else(Error::invalid_ansi("Missing 8-bit color"))?;

    
    

    to-html/crates/ansi-to-html/src/color.rs

    Lines 71 to 73 in f95215d

    	let r = r.ok_or_else(Error::invalid_ansi("Missing ANSI red"))?;
    	let g = g.ok_or_else(Error::invalid_ansi("Missing ANSI green"))?;
    	let b = b.ok_or_else(Error::invalid_ansi("Missing ANSI blue"))?;

    
    

    to-html/crates/ansi-to-html/src/color.rs

    Lines 78 to 80 in f95215d

    	return Err(Error::InvalidAnsi {
    	msg: format!("Expected 2 or 5, got {}", code),
    	})

---

I think it would be reasonable to instead ignore all of the current errors as invalid ansi codes instead of bailing out with an error. We could take an (optional?) dependency on some logging library and log some warning instead, or we could have an API that allows for returning the converted texts along with errors (and if so I would recommend returning a span indicating where the problematic text is and a more well typed error than a message String)

[Aloso]

I think that's a good idea