3.4. mktoc.fsm

A finite state machine implementation.

exception mktoc.fsm.NullStateException

Bases: exceptions.Exception

Exception thrown when StateMachine has no state defined to handle the current input data.

class mktoc.fsm.StateMachine

Bases: object

Base class for building a finite state machine.

The state machine is controled by two externally provided data structures.

regex_obj

A compiled regex pattern instance that contains one or more named groups (i.e. (?P<name>...)) sub-patterns.

match_handlers

A dict that maps a handler function to a group name returned by a successful match in the regex_obj instance.

Warning

The change_state() method must be run to initialize the state machine before the StateMachine instance is called.

__call__(lines)

For each line of text in lines, a regex match is performed and a state handler function is called to finalize processing of the string.

Parameters:lines (list) – Input data consumed by state machine

change_state(regex_obj=None, match_handlers=None)

Modifies the control flow of the state machine.

Replaces the internal regex_obj or match_handlers. Using keywords, one paramter can be changed without effecting the other.

Parameters:

• regex_obj (regex) – Compiled regular expression object
• match_handlers (dict of callable()‘s) – handler functions map, keyed with regex_obj group name.