Ok, in lua it’s indeed simple:

\startluacode

list = {"foo", "bar", "baz"}

\stopluacode

\starttext

\startluacode

for i, v in ipairs(list) do

    if i == #list then

        tex.print("last:")

        tex.print(v)

    elseif i == 1 then

        tex.print("first:")

        tex.print(v)

    else

        tex.print("in between:")

        tex.print(v)

    end

end

\stopluacode

\stoptext

But, it’d still love to hear whether there is a solution on the tex side.

Denis

Von: Maier, Denis Christian (UB)
Gesendet: Montag, 2. Mai 2022 09:15
An: 'mailing list for ConTeXt users' <ntg-context@ntg.nl>
Betreff: process list items differently depending on position in list

Hi,

I need to process a comma separated list, and adapt the formatting according to the position of an item in the list (example below). Expected output would be:

{\bf foo

}, {\em bar} and baz.

Is that possible? Can I somehow get the position of an item in the list? (My understanding is that \processcommalist and \processcommacommand apply a command to each list item, but there is no such thing as «position in the list»... I hope I’m wrong here.)

Or is that something where using Lua would be a better choice?

Best,

Denis

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\define[1]\command

  {#1}

\define\somelist

  {foo, bar, baz}

\starttext

  \processcommacommand

    [\somelist]

    \command

\stoptext

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%