WIP: Add readline util

addons/godot_xterm/util/readline.gd

@@ -0,0 +1,108 @@
+# Copyright (c) 2021, Leroy Hopson (MIT License).
+tool
+extends Reference
+
+const KeyCodes = {
+	ESCAPE = "\u001b",
+	ENTER = "\r",
+	BACKSPACE = "\u0008",
+	UP_ARROW = "\u001b[A",
+	DOWN_ARROW = "\u001b[B",
+	LEFT_ARROW = "\u001b[D",
+	RIGHT_ARROW = "\u001b[C",
+}
+
+var terminal
+var _prompt: String
+var _cursor_pos_min: int
+var _cursor_pos: int
+var _line: String
+
+
+func _init(p_terminal) -> void:
+	terminal = p_terminal
+	assert(terminal.has_method("write"))
+	assert(terminal.has_signal("key_pressed"))
+	assert("cols" in terminal)
+	assert("rows" in terminal)
+
+
+func readline(prompt := "> ") -> String:
+	_prompt = prompt
+	_cursor_pos_min = prompt.length()
+	_cursor_pos = prompt.length()
+
+	terminal.write(_prompt)
+
+	var input = yield(terminal, "key_pressed")
+	while input[1].scancode != KEY_ENTER:
+		print(input[0])
+		match input[0]:
+			KeyCodes.BACKSPACE:
+				_backspace()
+			KeyCodes.UP_ARROW:
+				# TODO: History prev.
+				pass
+			KeyCodes.DOWN_ARROW:
+				# TODO: History next.
+				pass
+			KeyCodes.LEFT_ARROW, KeyCodes.RIGHT_ARROW:
+				# TODO: Implement Me!
+				pass
+			_:
+				terminal.write(input[0])
+				_line += input[0]
+				_cursor_pos += 1
+				if _cursor_pos > 0 and _cursor_pos % int(terminal.cols) == 0:
+					terminal.write("\u001bE")
+		input = yield(terminal, "key_pressed")
+
+	return _line
+
+
+func _backspace() -> void:
+	if _cursor_pos > _cursor_pos_min:
+		if _cursor_pos % int(terminal.cols) == 0:
+			terminal.write("\u001b[1A\u001b[%dC\u001b[K" % terminal.cols)
+		else:
+			terminal.write("\b \b")
+		_line = _line.substr(0, _cursor_pos - _cursor_pos_min - 1)
+		_cursor_pos -= 1
+
+
+func _refresh_line() -> void:
+	var num_rows := ceil(_cursor_pos / terminal.cols)
+	for _row in range(num_rows):
+		terminal.write("\r\u001b[2K\u001b[1A")
+	terminal.write("\r\u001b[1B%s%s" % [_prompt, _line])
+	_cursor_pos = _prompt.length()
+	_cursor_pos += _line.length()
+
+## TODO
+#func _add_history(line: String) -> void:
+#	_history.append(line)
+#
+#
+## TODO
+#func _load_history(filepath) -> int:
+#	var file := File.new()
+#	var err := file.open(filepath, File.READ)
+#	if err == OK:
+#		var line := file.get_line()
+#		while line != "":
+#			_history.append(line)
+#			line = file.get_line()
+#	file.close()
+#	return err
+#
+#
+## TODO
+#func _save_history(filepath) -> int:
+#	var file := File.new()
+#	var err := file.open(filepath, File.WRITE)
+#	if err == OK:
+#		for line in _history:
+#			assert(line is String)
+#			file.store_line(line)
+#	file.close()
+#	return err