Luaf*ck

codeString = ""
inputString = ""
commands = {"<",">",".",",","[","]","+","-"}
values = {}
iterator = 1
pointer = 1
running = false
input = false

for i = 1, 30000 do
    values[i] = 0
end


function on.paint(gc)
    if running then
        executeCode(gc)
    else
        writeCode(gc)
    end
end

function on.charIn(ch)
    if running == false then
        for i,v in pairs (commands) do
            if ch == v then
                codeString = codeString .. ch
                refresh()
            end
        end
    end
    if input then
        values[pointer] = string.byte(ch)
        input = false
    end
end

function on.backspaceKey()
    if running == false then
        if string.len(codeString) > 0 then
            codeString = string.sub(codeString, 1, string.len(codeString) - 1)
        end
    end
    refresh()
end

function on.enterKey()
    if running then
        running = false
    else
        running = true
    end
    refresh()
end

function writeCode(gc)
    gc:drawString(codeString, 0, 0, "top")
end

function executeCode(gc)
    local str = string.sub(codeString, iterator, iterator)
    if str == "," then
        input = true
    end
    if str == "." then
        gc:drawString(string.char(values[pointer]),0,0,"top")
    end
    if str == "<" then
        pointer = pointer - 1
        if pointer <= 0 then
            pointer = 30000
        end
    end
    if str == ">" then
        pointer = pointer + 1
        if pointer > 30000 then
            pointer = 1
        end
    end
    if str == "+" then
        values[pointer] = values[pointer] + 1
    end
    if str == "-" then
        values[pointer] = values[pointer] - 1
    end
    if str == "[" then
        if values[pointer] == 0 then
            while str ~= "]" do
                iterator = iterator + 1
                str = string.sub(codeString, iterator, iterator)
            end
        end
    end
    if str == "]" then
        if values[pointer] ~= 0 then
            while str ~= "[" do
                iterator = iterator - 1
                str = string.sub(codeString, iterator, iterator)
            end
        end
    end
    if input == false then
        iterator = iterator + 1
    end
    if iterator > string.len(codeString) then
        running = false
    end
    refresh()
end

function refresh()
    platform.window:invalidate()
end