def evaluate(self, tokenList):
"""Takes an expression in RPN notation and evaluates it"""
tempStack = []
print(tokenList)
try:
tokenList.reverse()
except AttributeError:
result = "Error: Invalid tokens!"
return result
while len(tokenList) > 0:
i = tokenList.pop()
if isFloat(i):
tempStack.append(i)
else:
op = find(i)
if len(tempStack) < op.ops:
print("Error: Insufficient values!")
break
else:
value = arithmetic(tempStack.pop(), tempStack.pop(), i)
tokenList.append(value)
if len(tokenList) == 1 and tempStack == []:
result = tokenList[0]
return result
if len(tokenList) > 1:
result = "Error: User input has too many values"
return result
def evaluate(self, tokenList):
"""Takes an expression in RPN notation and evaluates it"""
tempStack = []
print(tokenList)
try:
tokenList.reverse()
except AttributeError:
result = "Error: Invalid tokens!"
return result
while len(tokenList) > 0:
i = tokenList.pop()
if isFloat(i):
tempStack.append(i)
else:
op = find(i)
if len(tempStack) < op.ops:
print("Error: Insufficient values!")
break
else:
value = arithmetic(tempStack.pop(), tempStack.pop(), i)
tokenList.append(value)
if len(tokenList) == 1 and tempStack == []:
result = tokenList[0]
return result
if len(tokenList) > 1:
result = "Error: User input has too many values"
return result
def shunting(self, exp):
"""Takes an expression in infix notation and converts it
to Reverse Polish Notation (RPN) using Dijkstra's
Shunting Yard Algorithm."""
stack = []
output = []
tempString = ""
# Get rid of all spaces for easier computation
try:
exp = exp.replace(' ', '')
except AttributeError:
return "Invalid type, string expected!"
# Mathematical Sin, Cos, Tan functions, decimals and PI are allowed
validChars = set("sincostanpi.")
foundLeftParan = False
validOutput = True
functions = ("sin", "cos", "tan")
if exp.count("(") != exp.count(")"):
output = "Error: Mismatched parantheses!"
print(output)
return output
# Tokenize the expression char by char
for i in exp:
# Store chars to see if they're number, function or constant
if i.isdigit() or i in validChars:
tempString += i
# Functions are handled here
elif tempString in functions:
stack.append(tempString)
# Operators are handled here
elif is_op(i):
# Token transition from number to operator. Get the number!
if len(tempString) > 0:
if tempString == "pi":
tempString = math.pi
output.append(float(tempString))
tempString = ""
# Find what operator it is
op = find(i)
# Remove operators from stack onto output according to
# their associativity and precedence.
# Parans need to be handled separately, see below.
while len(stack) > 0 and i != "(" and i != ")" and \
((op.ass == "l" and (op.pre <= find(stack[-1]).pre)) or \
(op.ass == "r" and (op.pre < find(stack[-1]).pre))):
output.append(stack.pop())
# Push the operator onto stack, unless it's right paran.
# Because it means the end of precedence, so whatever was
# inside those parans, they should be treated carefully
if i != ")":
stack.append(i)
# Ok, that means we've come to an end, the stack is probably
# stuffed up too much, so it's time put them in output.
elif i == ")":
while len(stack) > 0 and stack[-1] != "(":
output.append(stack.pop())
# Thank you dear left paran. You've served your purpose.
# It was a pleasure to work with you, but there is no need
# for you in RPN. You may go now!
if len(stack) > 0 and stack[-1] == "(":
stack.pop()
foundLeftParan = True
# And now for something completely (un)expected!
if len(stack) == 0 and not foundLeftParan:
output = "Error: Mismatched parantheses!"
validOutput = False
break
# Either users didn't read the instructions or they're delibaretely
# putting invalid chars in input! Go play with something else!
else:
output = "Invalid input!"
validOutput = False
break
# Remaining tokens (if any) are added to output
if len(tempString) > 0 and validOutput:
if tempString == "pi":
tempString = math.pi
output.append(float(tempString))
# Remaining operators (if any) in the stack are added to the output.
while len(stack) > 0:
if stack[-1] == "(" or stack[-1] == ")":
output = "Invalid input!"
break
if validOutput:
output.append(stack.pop())
return output
def shunting(self, exp):
"""Takes an expression in infix notation and converts it
to Reverse Polish Notation (RPN) using Dijkstra's
Shunting Yard Algorithm."""
stack = []
output = []
tempString = ""
# Get rid of all spaces for easier computation
try:
exp = exp.replace(' ','')
except AttributeError:
return "Invalid type, string expected!"
# Mathematical Sin, Cos, Tan functions, decimals and PI are allowed
validChars = set("sincostanpi.")
foundLeftParan = False
validOutput = True
functions = ("sin", "cos", "tan")
if exp.count("(") != exp.count(")"):
output = "Error: Mismatched parantheses!"
print(output)
return output
# Tokenize the expression char by char
for i in exp:
# Store chars to see if they're number, function or constant
if i.isdigit() or i in validChars:
tempString += i
# Functions are handled here
elif tempString in functions:
stack.append(tempString)
# Operators are handled here
elif is_op(i):
# Token transition from number to operator. Get the number!
if len(tempString) > 0:
if tempString == "pi":
tempString = math.pi
output.append(float(tempString))
tempString = ""
# Find what operator it is
op = find(i)
# Remove operators from stack onto output according to
# their associativity and precedence.
# Parans need to be handled separately, see below.
while len(stack) > 0 and i != "(" and i != ")" and \
((op.ass == "l" and (op.pre <= find(stack[-1]).pre)) or \
(op.ass == "r" and (op.pre < find(stack[-1]).pre))):
output.append(stack.pop())
# Push the operator onto stack, unless it's right paran.
# Because it means the end of precedence, so whatever was
# inside those parans, they should be treated carefully
if i != ")":
stack.append(i)
# Ok, that means we've come to an end, the stack is probably
# stuffed up too much, so it's time put them in output.
elif i == ")":
while len(stack) > 0 and stack[-1] != "(":
output.append(stack.pop())
# Thank you dear left paran. You've served your purpose.
# It was a pleasure to work with you, but there is no need
# for you in RPN. You may go now!
if len(stack) > 0 and stack[-1] == "(":
stack.pop()
foundLeftParan = True
# And now for something completely (un)expected!
if len(stack) == 0 and not foundLeftParan:
output = "Error: Mismatched parantheses!"
validOutput = False
break
# Either users didn't read the instructions or they're delibaretely
# putting invalid chars in input! Go play with something else!
else:
output = "Invalid input!"
validOutput = False
break
# Remaining tokens (if any) are added to output
if len(tempString) > 0 and validOutput:
if tempString == "pi":
tempString = math.pi
output.append(float(tempString))
# Remaining operators (if any) in the stack are added to the output.
while len(stack) > 0:
if stack[-1] == "(" or stack[-1] == ")":
output = "Invalid input!"
break
if validOutput:
output.append(stack.pop())
return output
