Wrt formatting (e.g. \index{\emph{something}}), the garden also mentions
processors for MkIV (https://wiki.contextgarden.net/Registers#Processors),
so you can wrap them with custom commands, in case it helps.

Cordially,

Jairo.

El sáb., 1 de ago. de 2020 a la(s) 14:01, Jairo A. del Rio (
jairoadelrio6@gmail.com) escribió:

> Hi, Henning. According to the garden, something like:
>
> \def\Ort#1{\index[#1]{\ctxlua{user.Lookup("#1")}}}
>
> as long as #1 is capable of being sorted in the normal way, should work.
>
> Regards,
>
> Jairo
>
> El sáb., 1 de ago. de 2020 a la(s) 13:49, Henning Hraban Ramm (
> texml@fiee.net) escribió:
>
>>
>>
>> > Am 01.08.2020 um 13:22 schrieb Henning Hraban Ramm <texml@fiee.net>:
>> >
>> > Hi,
>> >
>> > besides the CG journal I’m working on a scientific biography with huge
>> person and locality indexes (named Person and Locality for the examples).
>> >
>> > In many cases, the author wants additional information in the index,
>> e.g.
>> >
>> > \Locality{Altona (Hamburg)}
>> > \Locality{Breslau (pol. Wrocław)}
>> > or
>> > \Person{Arends, Katharina (née Schoemaker)}
>> > \Person{Wilhelm II. (Kaiser)}
>> >
>> > Now, I need that consistent and I don’t want to type these complicated
>> entries every time.
>> >
>> > I’m looking for a good way to handle this – maybe a lookup table in
>> Lua, so that
>> > \LookupPerson{Willy II}
>> > would call a Lua function that returns
>> > \Person{Wilhelm II. (Kaiser)}
>> > ?
>> >
>> > Or is there already something in place that I overlooked, like
>> > \OverwriteIndexEntry{Hraban}{Ramm, Henning Hraban}
>> > ?
>>
>> I came up with:
>>
>> \startluacode
>> user.Lookups = {
>>   ["Albano"] = "Albano (Provinz Rom)",
>>   ["Altona"] = "Altona (Hamburg)",
>>   ["Aurich"] = "Aurich (Ostfriesland)"
>> }
>>
>> function user.Lookup(Name)
>>   local Res = user.Lookups[Name]
>>   if Res then
>>     return context(Res)
>>   else
>>     return context(Name)
>>   end
>> end
>> \stopluacode
>>
>> \def\Ort#1{\index{\ctxlua{user.Lookup("#1")}}}
>>
>> \starttext
>>
>> \Ort{Albano}
>> \Ort{Altona}
>> \Ort{Aurich}
>> \strut\page
>>
>> \placeindex
>>
>> \stoptext
>>
>>
>> The lookup works so far, but all the entries get sorted unter C (because
>> of \ctxlua).
>>
>> I remember I had the same problem with other macros (like
>> \index{\emph{bla}}), but can’t find a solution in my usual sources.
>>
>>
>> Hraban
>>
>>
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>