forth_stack.v2.py

from __future__ import print_function
import time

input = '10 20 100 + - 20 * DUP 10 20 + *';

t = time.time()

for x in xrange(0, 100000):
    stack = []
    for chunk in input.split(' '):
        if chunk == '+':
            stack.append(stack.pop() + stack.pop())
        elif chunk == '-':
            stack.append(stack.pop() - stack.pop())
        elif chunk == '*':
            stack.append(stack.pop() * stack.pop())
        elif chunk == '=':
            stack.append(stack.pop() == stack.pop())
        elif chunk == 'DUP':
            stack.append(stack[0])
        elif chunk == 'DUMP':
            print(stack)
        else:
            stack.append(int(chunk))


print('Python list: %f' % (time.time() - t))
print(stack)

forth_stack.v3.py

from __future__ import print_function
import time


def forth_calc(input):
    stack = []
    for chunk in input.split(' '):
        if chunk == '+':
            stack.append(stack.pop() + stack.pop())
        elif chunk == '-':
            stack.append(stack.pop() - stack.pop())
        elif chunk == '*':
            stack.append(stack.pop() * stack.pop())
        elif chunk == '=':
            stack.append(stack.pop() == stack.pop())
        elif chunk == 'DUP':
            stack.append(stack[0])
        elif chunk == 'DUMP':
            print(stack)
        else:
            stack.append(int(chunk))
    return stack

input = '10 20 100 + - 20 * DUP 10 20 + *'

t = time.time()
for x in xrange(0, 100000):
    forth_calc(input)
print('Python list: %f' % (time.time() - t))
print(forth_calc(input))

forth_stack.v4.py

from __future__ import print_function
import time


def forth_calc(input):
    stack = []
    append = stack.append
    pop = stack.pop
    for chunk in input.split(' '):
        if chunk == '+':
            append(pop() + pop())
        elif chunk == '-':
            append(pop() - pop())
        elif chunk == '*':
            append(pop() * pop())
        elif chunk == '=':
            append(pop() == pop())
        elif chunk == 'DUP':
            append(stack[-1])
        elif chunk == 'DUMP':
            print(stack)
        else:
            append(int(chunk))
    return stack

input = '10 20 100 + - 20 * DUP 10 20 + *'

t = time.time()
for x in xrange(0, 100000):
    forth_calc(input)
print('Python list: %f' % (time.time() - t))
print(forth_calc(input))