Trouble using eval() with cython

Question

I was trying to speed up some code, and then I tried compiling a class and a function using cython

and WOW! I havn't measured it yet but it looks at least 10x faster.

I first looked at cython just two days ago, I'm very impressed!

However, I can't get eval() to work.

def thefirst(int a):
    d = eval('1+2+a')
    return d

I compile this to module1.pyd file and call it with the python file:

from module1 import thefirst
x = thefirst(2)
print x

This returns:

NameError: name 'a' is not defined.

All help is appreciated.

Answer 1

This is because eval has no way of examining the environment to find a. Use the locals function to pass it the environment.

def thefirst(a):
    return eval('1+2+a', locals())

Answer 2

Hmm, I'd think eval would be fairly bad for performance in any case. What is your actual use case?