[isabelle-dev] Wrong position information in 3bfa28b3a5b2

Makarius makarius at sketis.net
Fri Feb 22 22:59:33 CET 2019

On 22/02/2019 16:47, Manuel Eberl wrote:
> I came upon a regrssion with the position information in terms that
> contain calligraphic or Fraktur letters, e.g.:
> theory Scratch
>   imports Pure
> begin
> lemma "𝒜 𝒜 𝒜 𝒜 ()) a b c d e"
> The syntax error in this line is at the second closing parenthesis. In
> 3bfa28b3a5b2, Isabelle/jEdit displays the error at the space between "a"
> and "b".

Thanks for keeping an eye on isabelle-dev versions.

This is a problem introduced by Java 11: it works fine with Java 8. (I
will investigate it further later.)

> Each "𝒜" seems to shift the offset
> further, so I guess there's an off-by-one error in there somewhere.
> Interestingly, not all letters cause this – e.g. "ℳ" seems to be fine.

The calligraphic "A" belongs to a different Unicode standard than the
calligraphc "M". E.g. see these results in Console / BeanShell or
Console / Scala:

> "𝒜".length()
> "ℳ".length()


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