get dictionary definitions

dict.lua

#!/usr/bin/env lua

local host, port = "all.dict.org", 2628
local socket = require("socket")
local tcp = assert(socket.tcp())

-- rfc: https://tools.ietf.org/html/rfc2229
-- list databases: SHOW DB
-- get definition: DEFINE gcide loquacious

function dictionary(query)
    tcp:connect(host, port);
    tcp:send(("DEFINE * %s\n"):format(query));

    while true do
        local response = tcp:receive()
        local status = response:match('^(%d%d%d) ') or nil

        if status == nil then
            print(response)
        elseif status == '552' then
            print('No definition available')
            break
        elseif status == '501' then
            print('Syntax error')
            break
        elseif status == '250' then
            break
        end
    end
    tcp:close()
end

if #arg == 0 then
    print('Please give me a search term: dict.lua "<search>"\n')
else
    local query = ("'%s'"):format(table.concat(arg, ' '))
                          :gsub('%s+', ' ')
                          :gsub('^%s*(.-)%s*$', '%1')
    dictionary(query)
end