Grammalecte  Check-in [ac1f358667]

#!python3

"""
RULE GRAPH BUILDER
"""

# by Olivier R.
# License: MPL 2






from graphspell.progressbar import ProgressBar



class DARG:
    """DIRECT ACYCLIC RULE GRAPH"""
    # This code is inspired from Steve Hanov’s DAWG, 2011. (http://stevehanov.ca/blog/index.php?id=115)

    def __init__ (self, lRule, sLangCode):
        print("===== Direct Acyclic Rule Graph - Minimal Acyclic Finite State Automaton =====")

        # Preparing DARG
        print(" > Preparing list of tokens")
        self.sLangCode = sLangCode
        self.nRule = len(lRule)
        self.aPreviousRule = []
        Node.resetNextId()
        self.oRoot = Node()
        self.lUncheckedNodes = []  # list of nodes that have not been checked for duplication.
        self.lMinimizedNodes = {}  # list of unique nodes that have been checked for duplication.
        self.nNode = 0
        self.nArc = 0

        # build
        lRule.sort()
        oProgBar = ProgressBar(0, len(lRule))
        for aRule in lRule:
            self.insert(aRule)
            oProgBar.increment(1)
        oProgBar.done()
        self.finish()
        self.countNodes()
        self.countArcs()
        self.displayInfo()

    # BUILD DARG
    def insert (self, aRule):
        "insert a new rule (tokens must be inserted in order)"
        if aRule < self.aPreviousRule:
            exit("# Error: tokens must be inserted in order.")

        # find common prefix between word and previous word
        nCommonPrefix = 0
        for i in range(min(len(aRule), len(self.aPreviousRule))):
            if aRule[i] != self.aPreviousRule[i]:
                break
            nCommonPrefix += 1

            oNode = self.lUncheckedNodes[-1][2]

        iToken = nCommonPrefix
        for sToken in aRule[nCommonPrefix:]:
            oNextNode = Node()
            oNode.dArcs[sToken] = oNextNode
            self.lUncheckedNodes.append((oNode, sToken, oNextNode))
            if iToken == (len(aRule) - 2):
                oNode.bFinal = True
            iToken += 1
            oNode = oNextNode
        oNode.bFinal = True
        self.aPreviousRule = aRule

    def finish (self):

                oNode.dArcs[sToken] = self.lMinimizedNodes[oChildNode]
            else:
                # add the state to the minimized nodes.
                self.lMinimizedNodes[oChildNode] = oChildNode
            self.lUncheckedNodes.pop()

    def countNodes (self):
        "count nodes within the whole graph"
        self.nNode = len(self.lMinimizedNodes)

    def countArcs (self):
        "count arcs within the whole graph"
        self.nArc = 0
        for oNode in self.lMinimizedNodes:
            self.nArc += len(oNode.dArcs)

    def displayInfo (self):
        "display informations about the rule graph"
        print(" * {:<12} {:>16,}".format("Rules:", self.nRule))
        print(" * {:<12} {:>16,}".format("Nodes:", self.nNode))
        print(" * {:<12} {:>16,}".format("Arcs:", self.nArc))

    def createGraph (self):
        "create the graph as a dictionary"
        dGraph = { 0: self.oRoot.getNodeAsDict() }
        for oNode in self.lMinimizedNodes:
            sHashId = oNode.__hash__()
            if sHashId not in dGraph:
                dGraph[sHashId] = oNode.getNodeAsDict()
            else:
                print("Error. Double node… same id: ", sHashId)
                print(str(oNode.getNodeAsDict()))
        return dGraph



class Node:
    """Node of the rule graph"""

    NextId = 0

    def __init__ (self):
        self.i = Node.NextId
        Node.NextId += 1
        self.bFinal = False
        self.dArcs = {}          # key: arc value; value: a node

    @classmethod
    def resetNextId (cls):
        "reset to 0 the node counter"
        cls.NextId = 0

    def __str__ (self):
        # Caution! this function is used for hashing and comparison!
        cFinal = "1"  if self.bFinal  else "0"
        l = [cFinal]
        for (key, oNode) in self.dArcs.items():
            l.append(str(key))
            l.append(str(oNode.i))
        return "_".join(l)

    def __hash__ (self):
        # Used as a key in a python dictionary.
        return self.__str__().__hash__()

    def __eq__ (self, other):
        # Used as a key in a python dictionary.
        # Nodes are equivalent if they have identical arcs, and each identical arc leads to identical states.
        return self.__str__() == other.__str__()

    def getNodeAsDict (self):
        "returns the node as a dictionary structure"
        dNode = {}
        dReValue = {}
        dReMorph = {}
        dRule = {}