history.py

#!/usr/bin/env python
#coding=utf-8

'''
Definition of History class. It stores all pairs of {state, action} that the transition system
generated so far.

@author: Marco Damonte (m.damonte@sms.ed.ac.uk)
@since: 03-10-16
'''

class History:
    def __init__(self):
        self.states = []
        self.actions = []
        self.alignments = []

    def add(self, state, action, token):
        self.states.append(state)
        self.actions.append(action)
        if action.name == "shift":
            nodes = []
            for a in action.argv.nodes:
                if a.var is not None:
                    nodes.append(a.var)
                else:
                    nodes.append(a.constant)
            self.alignments.append((token,nodes))

    def statesactions(self):
        return [(state, action) for state, action in zip (self.states, self.actions)]

    def lastActions(self, K):
        actions = [item.get_id() for item in self.actions[::-1][0:K]]
        for i in range(len(actions),K):
            actions.append(0)
        return actions