def evalTree(tree): # evaluates and simplifies a tree (as far as it can go without hitting a variable) that you give it
if tree.isNumber():
return tree
elif tree.isOperator(): # +, -, *, /
left = evalTree(tree.left) # eval and set up copies of the tree branches
right = evalTree(tree.right)
if left.isOperator() or right.isOperator() or (left.isPoly() and right.isPoly() and right.value.var != left.value.var): # if left side is op, or right side is op, pass up. If both sides are vars, and they don't match, pass up.
tree.left = left
tree.right = right
return tree
num1 = left.value
num2 = right.value
if tree.value == "+": answer = num1 + num2 # evaluate ops
elif tree.value == "-": answer = num1 - num2
elif tree.value == "*": answer = num1 * num2
elif tree.value == "/": answer = num1 / num2
elif tree.value == "^" or tree.value == "**": answer = num1 ** num2
if INTERMEDIATE: print "\t"+str(num1)+str(tree.value)+str(num2)+"="+str(answer) # ...[+, -, *, /,etc.]...=...
result = Tree(answer, NUMBER, None, None)
if result.value.__class__ == Polynomial:
result.type = NAME
return result
elif tree.isFunction():
num = evalTree(tree.left) # make sure it is a number
if not num.isNumber(): # if not (such as var) pass it up
return tree
evalString = tree.value+"("+str(num.value)+")" # setting up the function...
answer = eval(evalString) # ...and evaling it
if INTERMEDIATE: print "\t"+evalString+"="+str(answer) # f(x)=...
result = Tree(answer, NUMBER, None, None)
return result
elif tree.isPoly():
return tree
else:
raise SyntaxError
