Maybe similar to the "spreadsheet" question: I'm trying to use Wolfgang's letter module for my invoices and would like to use Lua for the sums. But I fail already at the beginning: \startluacode userdata = userdata or {} userdata.invoice = userdata.invoice or { sum = 0 } -- global table for sums function userdata.singlesum(hours, perhour) amount = hours * perhour userdata.invoice.sum = userdata.invoice.sum + amount global.context(string.gsub(string.format("\%.2f", amount), "%.", ",")) return amount end \stopluacode gives: (virtual://viafile.1 unknown preamble key [the character )] unknown preamble key [the character )] unknown preamble key [the character )] ! LuaTeX error <main ctx instance>:1: '=' expected near '<eof>'. system > tex > error on line 11 in file invoice.tex: LuaTeX error ... 4 \startluacode 5 userdata = userdata or {} 6 7 userdata.invoice = userdata.invoice or { sum = 0 } 8 9 function userdata.singlesum(hours, perhour) 10 amount = hours * perhour 11 >> userdata.invoice.sum = userdata.invoice.sum + amount 12 global.context(string.gsub(string.format("\%.2f", amount), "%.", ",")) 13 return amount 14 end I can't see what's wrong!? I tried local and usercode, but didn’t get further. Greetlings from Lake Constance! Hraban --- http://www.fiee.net/texnique/ http://wiki.contextgarden.net https://www.cacert.org (I'm an assurer)