class While(Statement):
def __init__(self, tokens):
self.t = TokenHandler(tokens)
def execute(self, skip):
self.t.match("while", self.t.tokens)
conditiontokens = []
conditionistrue = self.t.ConditionIsTrue(self.t.tokens, conditiontokens)
self.t.match("do", self.t.tokens)
tokensexecuted = None
while(conditionistrue):
copytokens = list(self.t.tokens)
s = self.createStatement(copytokens)
tokensexecuted = s.execute(skip)
copytokens = list(conditiontokens)
conditiontokens = None
conditiontokens = []
conditionistrue = self.t.ConditionIsTrue(copytokens, conditiontokens)
size = len(self.t.executedtokens)
i = size - 1
while(i >= size - len(conditiontokens)):
self.t.executedtokens.pop(i)
i -= 1
self.t.moveAhead(tokensexecuted)
return self.t.resetTokens()
class Print(Statement):
def __init__(self, tokens):
self.t = TokenHandler(tokens)
def execute(self, skip):
self.t.match("print", self.t.tokens)
nexttoken = self.t.getCurrentToken()
if not skip:
print(self.t.readTokenValue(nexttoken))
self.t.match(nexttoken, self.t.tokens)
return self.t.resetTokens()
class ProgramStatement(Statement):
programName = None
def __init__(self, tokens):
self.t = TokenHandler(tokens)
def execute(self, skip):
self.t.match("program", self.t.tokens)
currentToken = self.t.getCurrentToken()
if not skip:
self.programName = currentToken
self.t.match(currentToken, self.t.tokens)
copytokens = list(self.t.tokens)
c = CompoundStatement(copytokens)
tokensExecuted = c.execute(skip)
self.t.moveAhead(tokensExecuted)
return self.t.resetTokens()
class CompoundStatement(Statement):
def __init__(self, tokens):
self.t = TokenHandler(tokens)
def execute(self, skip):
self.t.match("begin", self.t.tokens)
currenttoken = self.t.getCurrentToken()
condition = True
while condition == True:
copytokens = list(self.t.tokens)
currentstatement = self.createStatement(copytokens)
tokensexecuted = currentstatement.execute(skip)
self.t.moveAhead(tokensexecuted)
currenttoken = self.t.getCurrentToken()
if currenttoken == ";":
condition = True
self.t.match(";", self.t.tokens)
else:
condition = False
self.t.match("end", self.t.tokens)
return self.t.resetTokens()
class Assignment(Statement):
def __init__(self, tokens):
self.t = TokenHandler(tokens)
def execute(self, skip):
currenttoken = self.t.getCurrentToken()
if not self.t.isVariable(currenttoken):
raise VariableException("Not a variable: " + currenttoken)
variablebeingassigned = currenttoken
self.t.match(currenttoken, self.t.tokens)
self.t.match(":=", self.t.tokens)
currenttoken = self.t.getCurrentToken()
variablevalue = None
if not skip:
variablevalue = self.t.readTokenValue(currenttoken)
TokenHandler.variables[variablebeingassigned] = variablevalue
self.t.match(currenttoken, self.t.tokens)
currenttoken = self.t.getCurrentToken()
while(self.t.isMathOperator(currenttoken)):
if currenttoken == "+":
self.t.match("+", self.t.tokens)
currenttoken = self.t.getCurrentToken()
if not skip:
operand = self.t.readTokenValue(currenttoken)
variablevalue += operand
TokenHandler.variables[variablebeingassigned] = variablevalue
self.t.match(currenttoken, self.t.tokens)
elif currenttoken == "-":
self.t.match("-", self.t.tokens)
currenttoken = self.t.getCurrentToken()
if not skip:
operand = self.t.readTokenValue(currenttoken)
variablevalue -= operand
TokenHandler.variables[variablebeingassigned] = variablevalue
self.t.match(currenttoken, self.t.tokens)
elif currenttoken == "*":
self.t.match("*", self.t.tokens)
currenttoken = self.t.getCurrentToken()
if not skip:
operand = self.t.readTokenValue(currenttoken)
variablevalue *= operand
TokenHandler.variables[variablebeingassigned] = variablevalue
self.t.match(currenttoken, self.t.tokens)
elif currenttoken == "/":
self.t.match("/", self.t.tokens)
currenttoken = self.t.getCurrentToken()
if not skip:
operand = self.t.readTokenValue(currenttoken)
if operand == 0:
raise ParserException("Can't divide by zero.")
variablevalue /= operand
TokenHandler.variables[variablebeingassigned] = variablevalue
self.t.match(currenttoken, self.t.tokens)
currenttoken = self.t.getCurrentToken()
return self.t.resetTokens()
class IF(Statement):
def __init__(self, tokens):
self.t = TokenHandler(tokens)
def execute(self, skip):
self.t.match("if", self.t.tokens)
currenttoken = self.t.getCurrentToken()
if(skip):
while(currenttoken != "else"):
self.t.match(currenttoken, self.t.tokens)
currenttoken = self.t.getCurrentToken()
self.t.match("else", self.t.tokens)
copytokens = list(self.t.tokens)
s = self.createStatement(copytokens)
tokensexecuted = s.execute(skip)
self.moveAhead(tokensexecuted)
if(self.t.ConditionIsTrue(self.t.tokens, outcondition = [])):
self.t.match("then", self.t.tokens)
copytokens = list(self.t.tokens)
s = self.createStatement(copytokens)
tokensexecuted = s.execute(skip)
self.t.moveAhead(tokensexecuted)
self.t.match("else", self.t.tokens)
copytokens = list(self.t.tokens)
s = self.createStatement(copytokens)
tokensexecuted = s.execute(True)
self.t.moveAhead(tokensexecuted)
else:
currenttoken = self.t.getCurrentToken()
while(currenttoken != "else"):
self.t.match(currenttoken, self.t.tokens)
currenttoken = self.t.getCurrentToken()
self.t.match("else", self.t.tokens)
copytokens = list(self.t.tokens)
s = self.createStatement(copytokens)
tokensexecuted = s.execute(skip)
self.t.moveAhead(tokensexecuted)
return self.t.resetTokens()
