If it looks stupid but works, it isn't stupid

cboost

Boost your python code by automatically converting it to C/C++ on the fly.

Everything happens automagically just by adding single import and a decorator.

Read more about current status, features, and bugs...

Example python code to count number of primes less than n:

def is_prime(n: int) -> bool:
    if n in (0, 1):
        return False
    if n in (2, 3):
        return True
    if n % 2 == 0:
        return False
    for d in range(3, n, 2):
        if n % d == 0:
            return False
        if d * d > n:
            break
    return True

def how_many_primes(limit: int) -> int:
    how_many: int = 0
    for i in range(2, limit):
        if is_prime(i):
            how_many += 1
    return how_many

if __name__ == '__main__':
    import sys
    try:
        n = int(sys.argv[1])
    except IndexError:
        print(f'usage: {sys.argv[0]} N')
        sys.exit(1)

    print(f'{how_many_primes(n) = }')

Using cboost

Just import cboost and decorate each function with cboost.make_cpp.

import cboost                           # <-- import

@cboost.make_cpp                        # <-- decorator
def is_prime(n: int) -> bool:
    ...

@cboost.make_cpp                        # <-- decorator
def how_many_primes(limit: int) -> int:
    ...

...

Not using cboost

You can temporarily disable cboost by calling cboost.disable() before calling decorated function.

You can also export CBOOST_DISABLE=1 before running the script.

Generated C/C++ code:

// Module translated by cboost
extern "C" {
int is_prime(long n);
long how_many_primes(long limit);
}
int is_prime(long n)
{
    if ((n == 0) || (n == 1)){
        return 0;
    }
    if ((n == 2) || (n == 3)){
        return 1;
    }
    if ((n % 2) == 0){
        return 0;
    }
    /* This was translated from something else (eg. range()): */
    for (auto d = 3; d < n; d += 2){
        if ((n % d) == 0){
            return 0;
        }
        if ((d * d) > n){
            break;
        }
    }
    return 1;
}

long how_many_primes(long limit)
{
    long how_many = 0;
    /* This was translated from something else (eg. range()): */
    for (auto i = 2; i < limit; ++i){
        if (is_prime(i)){
            how_many += 1;
        }
    }
    return how_many;
}

// End of module

Example benchmarks:

Without cboost:

$ time CBOOST_DISABLE=1 ./example_primes.py 10000000
Warning: cboost disabled by CBOOST_DISABLE
how_many_primes(n) = 664579

real	1m59.170s
user	1m58.989s
sys     0m0.112s

With cboost:

$ time ./example_primes.py 10000000
how_many_primes(n) = 664579

real	0m7.972s
user	0m7.957s
sys     0m0.012s

This simple example gives almost 15 times performance boost.

Testing environment:

• CPU: Intel(R) Core(TM) i5 CPU M 580 @ 2.67GHz
• Python: 3.10.1
• OS: Ubuntu 20.04.3 LTS
• Kernel: Linux 5.4.0-91-generic
• gcc: g++ (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0