bin:infer-encoding error conditions

[michaelhkay]

The spec says

If no effective encoding could be chosen, an error is raised.

It's not clear what error is raised.

Under Error conditions, it says

[[bin:invalid-encoding] is raised if $encoding is invalid for the given input.

Does this mean that the function must ensure that the input can be successfully decoded using the returned encoding? This seems wasteful, since decode-string() is going to repeat this test. If it doesn't mean this, what does it mean?

[michaelhkay]

Also, it's not clear whether the function should normalize the supplied $encoding name to lower-case.

[ChristianGruen]

Does this mean that the function must ensure that the input can be successfully decoded using the returned encoding? This seems wasteful, since decode-string() is going to repeat this test. If it doesn't mean this, what does it mean?

After further reflection, I will fully align the rules with fn:unparsed-text.

Also, it's not clear whether the function should normalize the supplied $encoding name to lower-case.

I will update this as proposed in #2361.