hack a lua repl into bin/tty.lua

src/bin/tty.lua

@@ -20,9 +20,39 @@ gpu.setBackground(0x000000)
 local w, h = gpu.getResolution()
 gpu.fill(1, 1, w, h, ' ')
 gpu.set(1, 1, string.format('%s // %s', _VERSION, _OSVERSION))
+gpu.set(1, 2, 'lua>')
 
 
-local cmd, x, y = '', 1, 2
+local cmd, x, y = '', 6, 2
+
+local env = setmetatable({}, {__index = _ENV}) --TODO pcall require() on __index
+
+local function doEval(code)
+	local f, err = load('return ' .. code, '=expr', 't', env)
+	if not f then
+		f, err = load(code, '=repl', 't', env)
+	end
+	if not f then
+		gpu.setForeground(0xff0000)
+		gpu.set(x, y, tostring(err))
+		gpu.setForeground(0xffffff)
+		y = y + 1
+		return
+	end
+
+	local results = table.pack(pcall(f))
+	if results[1] then
+		for i = 2, results.n do
+			gpu.set(x, y, tostring(results[i]))
+			y = y + 1
+		end
+	else
+		gpu.setForeground(0xff0000)
+		gpu.set(x, y, tostring(results[2]))
+		gpu.setForeground(0xffffff)
+		y = y + 1
+	end
+end
 
 local function onKey(ch, code)
 	gpu.bind(screen)
@@ -34,11 +64,11 @@ local function onKey(ch, code)
 		x = x - widthLast
 		cmd = cmd:sub(1, -2)
 	elseif code == 28 then --enter
-		gpu.set(1, y + 1, '> ')
+		x, y = 1, y + 1
-		gpu.set(3, y + 1, cmd)
+		doEval(cmd)
-		cmd = ''
+		x, cmd = 6, ''
-		x, y = 1, y + 2
+		gpu.set(1, y, 'lua>')
-	else
+	elseif ch ~= 0 then
 		ch = unicode.char(ch)
 		gpu.set(x, y, ch)
 		cmd = cmd .. ch