jbe/bsw@0: --[[--
jbe/bsw@0: for
jbe/bsw@0:   index,          -- index variable counting up from 1
jbe/bsw@0:   prefix          -- prefix string with index in square brackets to be used as a prefix for a key passed to param.get or param.get_list
jbe/bsw@0: in
jbe/bsw@0:   param.iterate(
jbe/bsw@0:     prefix        -- prefix to be followed by an index in square brackets and another key
jbe/bsw@0:   )
jbe/bsw@0: do
jbe/bsw@0:   ...
jbe/bsw@0: end
jbe/bsw@0: 
jbe/bsw@0: This function returns an interator function to be used in a for loop. The CGI GET/POST parameter (or internal parameter) with the name "prefix[len]" is read, where 'prefix' is the prefix passed as the argument and 'len' ist just the literal string "len". For each index from 1 to the read length the returned iterator function returns the index and a string consisting of the given prefix followed by the index in square brackets to be used as a prefix for keys passed to param.get(...) or param.get_list(...).
jbe/bsw@0: 
jbe/bsw@0: --]]--
jbe/bsw@0: 
jbe/bsw@0: function param.iterate(prefix)
jbe/bsw@0:   local length = param.get(prefix .. "[len]", atom.integer) or 0
jbe/bsw@0:   if not atom.is_integer(length) then
jbe/bsw@0:     error("List length is not a valid integer or nil.")
jbe/bsw@0:   end
jbe/bsw@0:   local index = 0
jbe/bsw@0:   return function()
jbe/bsw@0:     index = index + 1
jbe/bsw@0:     if index <= length then
jbe/bsw@0:       return index, prefix .. "[" .. index .. "]"
jbe/bsw@0:     end
jbe/bsw@0:   end
jbe/bsw@0: end