[isabelle-dev] font issues in Isabelle jedit

Makarius makarius at sketis.net
Thu Jan 4 13:11:40 CET 2018

On 02/01/18 19:34, Lawrence Paulson wrote:
> Fonts have been weird for me for some time (clearly wider than jedit
“thinks” they are) but now symbols are completely missing. E.g. I see
>   have "integral UNIV (indicator (S \<inter> T)) = integral UNIV
(\<lambda>a. if a \<in> S \<inter> T then 1::real else 0)"

On 03/01/18 23:22, Lawrence Paulson wrote:
> I seem to have fixed the problem by selecting
> File > Reload with encoding > UTF-8-Isabelle

I have misunderstood your original problem description: it was not about
fonts, but the character encoding.

I have also refined that recently, see Isabelle/3cf05d7cf174 with the
following text in the Isabelle/jEdit manual:

>   Technically, the Unicode interpretation of Isabelle symbols is an
>   ∗‹encoding› called ▩‹UTF-8-Isabelle› in jEdit (∗‹not› in the underlying
>   JVM). It is provided by the Isabelle Base plugin and enabled by default for
>   all source files in Isabelle/jEdit.
>   Sometimes such defaults are reset accidentally, or malformed UTF-8 sequences
>   in the text force jEdit to fall back on a different encoding like
>   ▩‹ISO-8859-15›. In that case, verbatim ``▩‹α›'' will be shown in the text
>   buffer instead of its Unicode rendering ``‹α›''. The jEdit menu operation
>   ∗‹File~/ Reload with Encoding~/ UTF-8-Isabelle› helps to resolve such
>   problems (after repairing malformed parts of the text).
>   If the loaded text already contains Unicode sequences that are in conflict
>   with the Isabelle symbol encoding, the fallback-encoding UTF-8 is used and
>   Isabelle symbols remain in literal ▩‹\<symbol>› form. The jEdit menu
>   operation ∗‹Utilities~/ Buffer Options~/ Character encoding› allows to
>   enforce the UTF-8-Isabelle, but this will also change original Unicode
>   text into Isabelle symbols when saving the file!


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