luacurl, how to post with OPT_HTTPPOST?

[startx <startx@...>]

hello and happy xmas.

after some confusion between lua-CURL and lua-cURL,
i try to understand how to send a POST using lua-curl.

i want to simulate something like

curl -d "article[title]=hello world&article[body]=this is my text"
https://mycms.com/new

i use a function like this to send the request and fetch the response
(as found on this list before)

function fetch(url)
    local text = {}
    local function WriteMemoryCallback(s)
        text[#text+1] = s
        return string.len(s)
    end
    local c = curl.easy_init()
    c:setopt(curl.OPT_URL, url)
    c:setopt(curl.OPT_WRITEFUNCTION, WriteMemoryCallback)
    c:setopt(curl.OPT_USERAGENT, "luacurl-agent/1.0") c:perform()
    return table.concat(text,'')
end

now i found in the documentation that there is the option
curl.OPT_HTTPPOST , but whatebver option i set, table or string,
it always tells me "table expected, not string".

or do i look into the wrong option here?

so i am a bit lost  ... as a word of warning, im not a wizard with
libcurl itself so i know little about the internas.

startx