BUFFER

local w,h = term.getSize()
local buffer = {}

function initBuffer()
    for x=1,w do
        buffer[x] = {}
        for y = 1,h do
            buffer[x][y] = {}
        end
    end
end

function writeToBuffer(char,col,back,x,y)
    buffer[x][y] = {char,col,back}
end

function displayBuffer()
    rednet.broadcast(textutils.serialize(buffer),"stream")
    for x = 1, #buffer do
        for y = 1, #buffer[x] do
            term.setCursorPos(x,y)
            if #buffer[x][y] == 3 then
                term.setTextColor(buffer[x][y][2])
                term.setBackgroundColor(buffer[x][y][3])
                term.write(buffer[x][y][1])
            end
        end
    end
end

term.clear()
initBuffer()
term.setCursorPos(1,1)
local cx,cy = 1,1
while true do
    local e = {coroutine.yield()}
    if e[1] == "char" then
        writeToBuffer(e[2],123,43,cx,cy)
        displayBuffer()
        if cx == w then
            cx = 1
            cy = cy + 1
        elseif cx < w then
            cx = cx + 1
        end
    elseif e[1] == "key" then
        if e[2] == keys.enter then
            cy = cy + 1
            cx = 1
        elseif e[2] == keys.backspace then
            if cx > 1 then
                cx = cx - 1
            elseif cx == 1 then
                cx = w
                cy = cy - 1
            end
            writeToBuffer(" ",colors.black,colors.black,cx,cy)
            displayBuffer()
        end
    end
end