I also came up with a two-step method but wasn’t sure if it was really applicable in the actual use case. My solution does not seem very elegant but handles Sean’s five examples properly:
> function double_match (s) >> local text = s:match('^(%a+)$') >> if text then >> return text, nil >> else >> return s:match('^(%a+);(%d+)') >> end >> end > = double_match('foo') foo nil > = double_match('foo;1') foo 1 > = double_match('foo;444') foo 444 > = double_match('foo;') nil > = double_match('foo23') nil
Peter
This version avoided "double matching", perhaps slightly more efficient:
function match2(s) if #s == 0 then return end local i = string.find(s, "%A") if i == nil then return s, nil end i = string.find(s, "^;%d+$", i) if i then return s:sub(1,i-1), s:sub(i+1) end end | 
