view.love/main.lua

require 'keychord'
local utf8 = require 'utf8'

lines = {}
width, height, flags = 0, 0, nil
exec_payload = nil

function love.load()
  table.insert(lines, '')
  love.window.setMode(0, 0)  -- maximize
  width, height, flags = love.window.getMode()
  love.keyboard.setTextInput(true)  -- bring up keyboard on touch screen
end

function love.draw()
  love.graphics.setColor(1, 1, 1)
  love.graphics.rectangle('fill', 1, 1, width-1, height-1)
  love.graphics.setColor(1, 1, 0)
  love.graphics.rectangle('fill', 1, 1, 400, 10*12)
  love.graphics.setColor(0, 0, 0)
  local text
  for i, line in ipairs(lines) do
    text = love.graphics.newText(love.graphics.getFont(), line)
    love.graphics.draw(text, 12, i*15)
  end
  -- cursor
  love.graphics.print('_', 12+text:getWidth(), #lines*15)

  if exec_payload then
    call_gather(exec_payload)
  end
end

function love.update(dt)
end

function love.textinput(t)
  lines[#lines] = lines[#lines]..t
end

function keychord_pressed(chord)
  -- Don't handle any keys here that would trigger love.textinput above.
  if chord == 'return' then
    table.insert(lines, '')
  elseif chord == 'backspace' then
    if #lines > 1 and lines[#lines] == '' then
      table.remove(lines)
    else
      local byteoffset = utf8.offset(lines[#lines], -1)
      if byteoffset then
        lines[#lines] = string.sub(lines[#lines], 1, byteoffset-1)
      end
    end
  elseif chord == 'C-r' then
    eval(lines[#lines])
--?     lines[#lines+1] = eval(lines[#lines])[1]
--?     lines[#lines+1] = ''
  end
end

function love.keyreleased(key, scancode)
end

function love.mousepressed(x, y, button)
end

function love.mousereleased(x, y, button)
end

function eval(buf)
  local f = load('return '..buf, 'REPL')
  if f then
    exec_payload = f
    return
--?     return call_gather(f)
  end
  local f, err = load(buf, 'REPL')
  if f then
    exec_payload = f
    return
--?     return call_gather(f)
  else
    return {err}
  end
end

-- based on https://github.com/hoelzro/lua-repl
function call_gather(f)
  local success, results = gather_results(xpcall(f, function(...) return debug.traceback() end))
  return results
end

function gather_results(success, ...)
  local n = select('#', ...)
  return success, { n = n, ... }
end