def eval_postfix(iter):
s = LinkedList() #s = stack
t = VarTree() #t = tree
for token in iter:
if (str(token)).isalnum():
s.push(token)
elif token == '=':
val = s.pop()
if not (str(val)
).isdigit(): #allows assigning one variable to another
val = t.lookup(
val
) #if it finds a variable, grabs its value from the tree
var = s.pop()
t.assign(str(var), val)
s.push(var)
else:
right = s.pop()
left = s.pop()
s.push(eval(str(left) + token + str(right)))
#the solution should be the only value in the stack
sol = s.pop()
if not (str(sol)).isdigit():
sol = t.lookup(sol)
return int(sol)
def evaluate(self, variables, functions):
x = functions.lookup(self._name)
y = VarTree()
for i in range(len(x[0])):
y.assign(x[0][i],
self._parameter[i].evaluate(variables, functions))
return x[1].evaluate(y, functions)
def evaluate(self, variables, functions):
temp = VarTree()
[params, body] = functions.lookup(self._name)
for i in range(len(params)):
par = params[i]
parVal = self._args[i].evaluate(variables, functions)
temp.assign(par, parVal)
return body.evaluate(temp, functions)
def evaluate(self, variables, functions): parms, body = functions.lookup(self._name) newTree = VarTree() for i in range(0, len(parms)): newTree.assign(parms[i], self._arg[i].evaluate(variables, functions)) return body.evaluate(newTree, functions)