do  -- find words whose characters are in alphabetical order

    local function isSorted( word : string ) : boolean
        for c = 1, # word - 1 do
            if word[ c ] > word[ c + 1 ] then return false end
        end
        return true
    end

    local sortedWords, maxLength = {}, 0
    for word in io.lines( "unixdict.txt" ) do
        if isSorted( word ) then
            local thisLength <const> = # word
            if thisLength >= maxLength then
                if thisLength > maxLength then
                    sortedWords, maxLength = {}, thisLength
                end
                sortedWords[ # sortedWords + 1 ] = word
            end
        end
    end
    for _, w in ipairs( sortedWords ) do print( w ) end

end