languages automatically inherit this definition, but
can optionally override it.
Alternatively, we could use cross-language inheritance as it is already used for some orthographies. To avoid introducing a new linking logic.
Design requirements/alternates should mention any language-specific preferences, e.g. Urdu preference differs from the default Persian numerals to which these are usually mapped. I am not sure this should be a shaping check that fails detection as some fonts may be designed with Urdu numerals as default.
From the top of my head, I do not see the case for auxiliary numerals. Maybe there is some? Even in the case of Devanagari, which has its own numerals, I would list also include the Latin-script numerals (I will not call these Arabic!) as both sets are used frequently.
Language detection should fail if the numerals are defined, but not included in the font.
We thought this approach would work well:
Alternatively, we could use cross-language inheritance as it is already used for some orthographies. To avoid introducing a new linking logic.
Design requirements/alternates should mention any language-specific preferences, e.g. Urdu preference differs from the default Persian numerals to which these are usually mapped. I am not sure this should be a shaping check that fails detection as some fonts may be designed with Urdu numerals as default.
From the top of my head, I do not see the case for auxiliary numerals. Maybe there is some? Even in the case of Devanagari, which has its own numerals, I would list also include the Latin-script numerals (I will not call these Arabic!) as both sets are used frequently.
Language detection should fail if the numerals are defined, but not included in the font.