Pasted

text = {}               -- this will store the text you type
buttons = {}            -- this will store all of your buttons (dont worry about it)
 
textBoxX = 1
textBoxY = 5
 
function addButton(text,x1,y1)
    buttons[text] = {pos1 = {x = x1,y = y1},pos2 = {x = string.len(text)+x1,y = y1}}
end
 
function drawButtons()
    for k,v in pairs(buttons) do
        term.setCursorPos(buttons[k].pos1.x,buttons[k].pos1.y)
        term.write(k)
    end
end
 
-- Here you can add your buttons
addButton("Iron Ingot",10,6)
addButton("Gold Ingot",10,7)
 
while true do
    event, keyNum, x, y = os.pullEvent()
    term.setCursorPos(textBoxX,textBoxY)
    term.clear()
    
    drawButtons()
    
    if (event == "key") then
        event, char = os.pullEvent()       
        if (tonumber(char) == nil) then
            table.insert(text,char)
            
       elseif (keyNum == 14) then
            table.remove(text,#text)
        end
    elseif (event == "mouse_up") then
        if (keyNum == 1) then
            for k,v in pairs(buttons) do
                if (x >= buttons[k].pos1.x and x <= buttons[k].pos2.x) then
                    if (y >= buttons[k].pos1.y and y <= buttons[k].pos2.y) then
                        term.setCursorPos(buttons[k].pos1.x-1,buttons[k].pos1.y)
                        term.write("["..k.."]")
                        -- k is the name of the item you added, you can do whatever you want with it after this write statement
                        -- inside of this if.
 
                    end
                end
            end
        elseif (keyNum == 2) then
            for i = 1,#text do
                if (x >= textBoxX and x <= (#text+textBoxX)) then
                    if (y == textBoxY) then
                        text = {}
                    end
                end
            end
        end
    end
    term.setCursorPos(1,5)
    for i = 1,#text do
        term.write(text[i])
    end
end