story_node.py

'''This class represents a distinct moment in an interactive story.
It will have fields for a name, description, necessary conditions to be
available, and child story events. Additionally, activities are attributed to
each node and allow for more interactivity between user and story'''
from activity import Activity
from nltk.stem.snowball import SnowballStemmer

stemmer = SnowballStemmer('english')

class StoryNode:
    # only necessary parameters are name and description
    def __init__(self, a_name, a_description = None, the_prereqs = None, the_children = None, an_activity = None):
        self.name = str(a_name)
        self.description = a_description
        # add prerequisites for story node to be valid
        self.prereqs = []
        if the_prereqs != None:
            for req in the_prereqs:
                self.prereqs.append(req)
        #a list to hold other words the user can say to represent the node
        self.syns = []
        for s in self.name.split():
            self.syns.append(stemmer.stem(s))       #use root of word for generality
        # add children StoryNodes to this node, possible edges in graph
        self.children = []
        self.children_stems = []
        if the_children != None:
            for child in the_children:
                if isinstance(child, StoryNode):
                    self.children.append(child)
                    self.children_stems.append(child.syns)
        # add activities to the node to be completed
        self.activity = None
        if an_activity != None:
            self.activity = an_activity
        

	# adds new children to a node, adding them to children list
    def addChild(self, child):
        if isinstance(child, StoryNode):
            self.children.append(child)
            self.children_stems.append(child.syns)
        else:
            print "child is not a StoryNode"
        return self

    #adds a prerequisite
    def addPrereq(self, prereq):
        self.prereqs.append(prereq)
        return self

	# adds new activities to a node
    def setActivity(self, activ): # an activity is simply a wrapper class for a user defined function (allows for customization of activities)
        if isinstance(activ, Activity):
            self.activity = activ
        else:
            print "not an Activity"
        return self