I believe it's a bug.

https://github.com/contextgarden/context/blob/d025bcdf995be6951f69fed6869048ab22491b9e/tex/context/base/mkxl/font-col.lmt#L278

the newchar[] table, which should contain all chars supported by the fallback termes font if I'm not mistaken, turns out to have only 392 chars within 0x20-0x30C, far away from 0x2329-0x232A.

On Sun, 23 Apr 2023 at 03:26, Thomas A. Schmitz via ntg-context <ntg-context@ntg.nl> wrote:
Thank you, Pablo, but that doesn't help. I know how to use fallback
fonts. I was wondering if the check key is working as it should.

Thomas

On 4/22/23 20:33, Pablo Rodriguez via ntg-context wrote:
> Hi Thomas,
>
> I don’t know what check does (maybe just check?), but the standard
> behaviour with \definefallbackfamily is only to fall back when the
> character is missing from the main font.
>
> To force all characters from the range in the fallback font, "force=yes"
> is required.
>
> Here you have a minimal sample (which doesn‘t use "preset=range:greek"),
> adding "force=yes" gets all Greek glyphs from GFS Heraklit:
>
>    \definefallbackfamily [presentation] [serif] [GFSHeraklit]
>    [range={greekandcoptic, greekextended}]
>    \definefontfamily [presentation] [serif] [TeXGyrePagella]
>    \setupbodyfont [presentation,12pt]
>
>    \starttext
>    Pπμᾷσδ
>    \stoptext
>
> Just in case it might help,

--
Prof. Dr. Thomas A. Schmitz
Institut für Klassische und Romanische Philologie
Universität Bonn
Am Hof 1e
53113 Bonn
http://www.philologie.uni-bonn.de/de/personal/schmitz

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