AToMPM/mt/ptcal/pytcore/rules/lqsrule.py

'''This file is part of AToMPM - A Tool for Multi-Paradigm Modelling
Copyright 2011 by the AToMPM team and licensed under the LGPL
See COPYING.lesser and README.md in the root of this project for full details'''

from ..util.infinity import INFINITY
from lrule import LRule
from symbol import try_stmt


class LQSRule(LRule):
    '''
        Applies an inner rule for each match of the LHS as long as matches can be found.
    '''
    def __init__(self, LHS, inner_rule, max_iterations=INFINITY):
        '''
            Applies an inner rule for each match of the LHS as long as matches can be found.
            @param LHS: The pre-condition pattern (LHS + NACs).
            @param inner_rule: The rule to apply in the loop.
            @param max_iterations: The maximum number of matches of the LHS.
        '''
        super(LQSRule, self).__init__(LHS, inner_rule, max_iterations)
    
    def packet_in(self, packet):
        self.exception = None
        self.is_success = False
        # Match
        packet = self.M.packet_in(packet)
        if not self.M.is_success:
            self.exception = self.M.exception
            return packet
        # Choose the first match
        packet = self.I.packet_in(packet)
        if not self.I.is_success:
            self.exception = self.I.exception
            return packet

        while True:
            # Apply the inner rule
            packet = self.inner_rule.packet_in(packet)
            if not self.inner_rule.is_success:
                if self.inner_rule.exception:
                    self.exception = self.inner_rule.exception
                return packet
            # Rule has been applied once, so it's a success anyway
            self.is_success = True
            
            
            if self.I.iterations == self.I.max_iterations:
                return packet
            
            ''' hergin :: motif-integration : clean Matchset before rematch because only LHS doesnot have a rewriter '''
            #packet.match_sets = {}
            #try:
            #    if  len(packet.match_sets[self.I.condition].matches) == 0:
            #        del packet.match_sets[self.I.condition]
            #except KeyError:
            #    pass
            
            # Re-Match
            packet = self.M.packet_in(packet)
            if not self.M.is_success:
                self.exception = self.M.exception
                return packet
             
            # Choose another match
            packet = self.I.next_in(packet)
            # No more iterations are left
            if not self.I.is_success:
                if self.I.exception:
                    self.exception = self.I.exception
                return packet