#2008173/31 хорошо, по примеру из /30

# node ::= 'node' node_command
parser.define('node').add_rule('node_command', name='node')

# node_command ::= node_list| node_attach | node_detach
node_command = parser.define('node_command')
node_command.add_alternatives('node_list')
node_command.add_alternatives('node_attach')
node_command.add_alternatives('node_detach')

# node_list ::= 'list'
parser.define('node_list').add_token('list')

def node_name_is_available(name=None, force=None, context=None):
	if node in list_of_node_names_from_database:
		if force:
			parser.warning('node "%s" would be replaced' % name)
		else:
			parser.error(context, 'node "%s" is already defined' % name)

def node_name_does_not_available(name=None, force=None, context=None):
	if not node in list_of_node_names_from_database:
		message = 'node "%s" does not found' % name
		if force:
			parser.warning('%s does not found')
	return not node_name_is_available(name=name)

# node_attach ::= 'attach' name connect_string optional_force
parser.define('node_attach').add_token('attach').add_rule('name', name='name').add_rule('connect_string').add_rule('optional_force', name='force').add_check(node_name_is_available)

# node_detach ::= 'detach' name optional_force
parser.define('node_detach').add_token('detach').add_rule('name', name='name', check=node_name_is_available).add_rule('connect_string').add_rule('optional_force')

# optional_force ::= '-f' | '--force' | eof
parser.define('optional_force').add_alternatives(parser.token('-f', value=True)).add_alternatives(parser.token('--force'), value=True).add_alternatives(parser.epsilon(), value=False)

# connect_string ::= connect_string_user connect_string_host connect_string_port
cs = parser.define('connect_string')
cs.add_rule('connect_string_user', name='user')
cs.add_rule('connect_string_host', name='host')
cs.add_rule('connect_string_port', name='port')

# connect_string_user ::= name '@'
parser.define('connect_string_user').add_rule('name').add_token('@', include_result=False)

# connect_string_host ::= name
parser.define('connect_string_user').add_rule('name')

# connect_string_port ::= ':' port
parser.define('connect_string_user').add_token(':', include_result=False).add_rule('port')

# port ::= int { > 1024 && < 2^16 }
parser.define('port').add_digit(condition=lambda x: x >= 1024 and x <= 2 ** 16)

# name ::= name_simple | name_complex
name = parser.define('name')
name.add_alternative('name_simple')
name.add_alternative('name_complex')

# name_simple ::= '[a-zA-Z]+[a-zA-Z0-9]*'
parser.define('name_simple').add_token('[a-zA-Z]+[a-zA-Z0-9]*')

# name_complex ::= '"' '[a-zA-Z]+[a-zA-Z0-9 ]*' '"'
parser.define('name_complex').add_token('"', include_result=False).add_token('[a-zA-Z]+[a-zA-Z0-9 ]*').add_token('"', include_result=False)