def find_follow(grammar):
follow_not_found_dictionary = {}
grammar_dictionary = {}
list_of_symbols_in_order = []
for eachGrammarProduction in grammar:
#removing extra spaces and new line character
eachGrammarProduction = eachGrammarProduction.split("->")
eachGrammarProduction[0] = eachGrammarProduction[0].replace(" ", "")
eachGrammarProduction[0] = eachGrammarProduction[0].replace("\n", "")
eachGrammarProduction[1] = eachGrammarProduction[1].replace(" ", "")
eachGrammarProduction[1] = eachGrammarProduction[1].replace("\n", "")
if not (eachGrammarProduction[0] in list_of_symbols_in_order):
list_of_symbols_in_order.append(eachGrammarProduction[0])
#if the same grammar has more than one production then add it to a list
if (grammar_dictionary.has_key(eachGrammarProduction[0])):
grammar_dictionary[eachGrammarProduction[0]].append(
eachGrammarProduction[1])
else:
grammar_dictionary[eachGrammarProduction[0]] = [
eachGrammarProduction[1]
]
follow_dictionary = {}
first = find_first(grammar_dictionary)
start_symbol = list_of_symbols_in_order[0]
follow_dictionary[start_symbol] = ['$']
for everySymbol in list_of_symbols_in_order[1:]:
follow_dictionary[everySymbol] = []
for everySymbol in list_of_symbols_in_order:
productions_found = find_productions(grammar_dictionary, everySymbol)
process_productions_found(productions_found, first, follow_dictionary,
follow_not_found_dictionary, everySymbol)
for everySymbol in follow_not_found_dictionary.keys():
if len(follow_not_found_dictionary[everySymbol]) != 0:
for NonTerminal in follow_not_found_dictionary[everySymbol]:
for eachTerminal in follow_dictionary[NonTerminal]:
if eachTerminal not in follow_dictionary[everySymbol]:
follow_dictionary[everySymbol].append(eachTerminal)
return follow_dictionary
def find_follow(grammar):
follow_not_found_dictionary ={}
grammar_dictionary = {}
list_of_symbols_in_order = []
for eachGrammarProduction in grammar:
#removing extra spaces and new line character
eachGrammarProduction = eachGrammarProduction.split("->")
eachGrammarProduction[0] = eachGrammarProduction[0].replace(" ","")
eachGrammarProduction[0] = eachGrammarProduction[0].replace("\n","")
eachGrammarProduction[1] = eachGrammarProduction[1].replace(" ","")
eachGrammarProduction[1] = eachGrammarProduction[1].replace("\n","")
if not(eachGrammarProduction[0] in list_of_symbols_in_order):
list_of_symbols_in_order.append(eachGrammarProduction[0])
#if the same grammar has more than one production then add it to a list
if(grammar_dictionary.has_key(eachGrammarProduction[0])):
grammar_dictionary[eachGrammarProduction[0]].append(eachGrammarProduction[1])
else:
grammar_dictionary[eachGrammarProduction[0]] = [eachGrammarProduction[1]]
follow_dictionary = {}
first = find_first(grammar_dictionary)
start_symbol = list_of_symbols_in_order[0]
follow_dictionary[start_symbol] = ['$']
for everySymbol in list_of_symbols_in_order[1:]:
follow_dictionary[everySymbol] =[]
for everySymbol in list_of_symbols_in_order:
productions_found = find_productions(grammar_dictionary,everySymbol)
process_productions_found(productions_found,first,follow_dictionary,follow_not_found_dictionary,everySymbol)
for everySymbol in follow_not_found_dictionary.keys():
if len(follow_not_found_dictionary[everySymbol]) != 0:
for NonTerminal in follow_not_found_dictionary[everySymbol]:
for eachTerminal in follow_dictionary[NonTerminal]:
if eachTerminal not in follow_dictionary[everySymbol]:
follow_dictionary[everySymbol].append(eachTerminal)
return follow_dictionary
def find_follow(grammar):
follow_not_found_dictionary = {}
grammar_dictionary = {}
list_of_symbols_in_order = []
for eachGrammarProduction in grammar:
eachGrammarProduction = eachGrammarProduction.split("->")
eachGrammarProduction[0] = eachGrammarProduction[0].replace(" ", "")
eachGrammarProduction[0] = eachGrammarProduction[0].replace("\n", "")
eachGrammarProduction[1] = eachGrammarProduction[1].replace(" ", "")
eachGrammarProduction[1] = eachGrammarProduction[1].replace("\n", "")
if not (eachGrammarProduction[0] in list_of_symbols_in_order):
list_of_symbols_in_order.append(eachGrammarProduction[0])
if (eachGrammarProduction[0] in grammar_dictionary):
grammar_dictionary[eachGrammarProduction[0]].append(
eachGrammarProduction[1])
else:
grammar_dictionary[eachGrammarProduction[0]] = [
eachGrammarProduction[1]
]
follow_dictionary = {}
first = find_first(grammar_dictionary)
start_symbol = list_of_symbols_in_order[0]
follow_dictionary[start_symbol] = ['$']
for everySymbol in list_of_symbols_in_order[1:]:
follow_dictionary[everySymbol] = []
for everySymbol in list_of_symbols_in_order:
productions_found = find_productions(grammar_dictionary, everySymbol)
process_productions_found(productions_found, first, follow_dictionary,
follow_not_found_dictionary, everySymbol)
for everySymbol in follow_not_found_dictionary:
if len(follow_not_found_dictionary[everySymbol]) != 0:
for NonTerminal in follow_not_found_dictionary[everySymbol]:
for eachTerminal in follow_dictionary[NonTerminal]:
if eachTerminal not in follow_dictionary[everySymbol]:
follow_dictionary[everySymbol].append(eachTerminal)
return follow_dictionary
def getFirst(self):
#print "first is called"
self.textBrowser_3 = QtGui.QTextBrowser(self.centralwidget)
self.textBrowser_3.setObjectName(_fromUtf8("textBrowser_3"))
self.gridLayout_3.addWidget(self.textBrowser_3, 1, 0, 1, 2)
first = []
if len(self.grammar_list) == 0:
self.showWarningMsg()
else:
grammar = {}
for eachElement in self.grammar_list:
eachElement = eachElement.replace(" ","")
production = eachElement.split("->")
if grammar.has_key(production[0]):
grammar[production[0]].append(production[1])
else:
grammar[production[0]] = [production[1]]
#print grammar
first = find_first(grammar)
#print first
self.showFirst(first)
def getFirst(self):
#print "first is called"
self.textBrowser_3 = QtGui.QTextBrowser(self.centralwidget)
self.textBrowser_3.setObjectName(_fromUtf8("textBrowser_3"))
self.gridLayout_3.addWidget(self.textBrowser_3, 1, 0, 1, 2)
first = []
if len(self.grammar_list) == 0:
self.showWarningMsg()
else:
grammar = {}
for eachElement in self.grammar_list:
eachElement = eachElement.replace(" ","")
production = eachElement.split("->")
if grammar.has_key(production[0]):
grammar[production[0]].append(production[1])
else:
grammar[production[0]] = [production[1]]
#print grammar
first = find_first(grammar)
#print first
self.showFirst(first)
