def takeFactor(self, tokens):
now = tokens.front()
if now == '(':
try:
tokens.popFront()
exp = self.takeExpression(tokens)
tokens.popFront()
except IndexError:
raise InvalidFormula()
return Paranthesis(exp)
elif Function.isSingleParamFunction(now) == True:
try:
self.functions.add(now)
tokens.popFront()
lparan = tokens.popFront()
exp = self.takeExpression(tokens)
rparan = tokens.popFront()
if (lparan == '(' and rparan == ')') == False:
raise InvalidFormula()
except IndexError:
raise InvalidFormula()
return Function.determine(now, param=exp)
elif Function.isDoubleParamFunction(now) == True:
try:
self.functions.add(now)
tokens.popFront()
lparan = tokens.popFront()
exp1 = self.takeExpression(tokens)
tokens.popFront()
exp2 = self.takeExpression(tokens)
rparan = tokens.popFront()
if (lparan == '(' and rparan == ')') == False:
raise InvalidFormula()
except IndexError:
raise InvalidFormula()
return Function.determine(now, base=exp1, exponential=exp2)
elif Number.isNumber(now) == True:
tokens.popFront()
return Number.determine(now)
elif now == '-':
try:
tokens.popFront()
fac = self.takeFactor(tokens)
term = Term([Number(-1), fac], ['*'])
expr = Expression([term], [])
except IndexError:
raise InvalidFormula()
return Paranthesis(expr)
elif Variable.isVariable(now) == True:
tokens.popFront()
return Variable(now)
else:
raise InvalidFormula()
def takeFactor(self, tokens):
now = tokens.front()
if now == '(':
try:
tokens.popFront()
exp = self.takeExpression(tokens)
tokens.popFront()
except IndexError:
raise InvalidFormula()
return Paranthesis(exp)
elif Function.isSingleParamFunction(now)==True:
try:
self.functions.add(now)
tokens.popFront()
lparan=tokens.popFront()
exp = self.takeExpression(tokens)
rparan=tokens.popFront()
if (lparan=='(' and rparan==')')==False:
raise InvalidFormula()
except IndexError:
raise InvalidFormula()
return Function.determine(now, param=exp)
elif Function.isDoubleParamFunction(now)==True:
try:
self.functions.add(now)
tokens.popFront()
lparan=tokens.popFront()
exp1 = self.takeExpression(tokens)
tokens.popFront()
exp2 = self.takeExpression(tokens)
rparan=tokens.popFront()
if (lparan=='(' and rparan==')')==False:
raise InvalidFormula()
except IndexError:
raise InvalidFormula()
return Function.determine(now, base=exp1, exponential=exp2)
elif Number.isNumber(now)==True:
tokens.popFront()
return Number.determine(now)
elif now == '-':
try:
tokens.popFront()
fac = self.takeFactor(tokens)
term=Term([Number(-1),fac],['*'])
expr=Expression([term],[])
except IndexError:
raise InvalidFormula()
return Paranthesis(expr)
elif Variable.isVariable(now)==True:
tokens.popFront()
return Variable(now)
else:
raise InvalidFormula()