dmishin / pseudo_generator Goto Github PK

Generators (continuations) for C++

Some languages, partcaularly, Python, support a very useful feature called "generators".
It is a special case of the thing, known as "continuations".

Here is a sample Python code for those, who by some reason do now know about them:

[pyton]

def primes():
    yield 2
    x = 3
    while True:
        for d in range( 
    

[/python]

Is there any way to implement this in C++?
Well, not really. 
Support for continuations require that execution state can be saved and restored arbitratily.
C++ model of execution does not allows this.

BOOST offers generators library, based on a trick with threads: generator code is effectively runned in the separate thread,
which eliminates the nececerity for saving execution state.

This offers excellent "real" genrators, just like in Python, but some may think about such approach as about overkill.

What I want is a simple, standart-compliant, low-overhead library, that can facilitate writing code in generator style.

ANd, here it is.

That's how you can implement the same genreator with this library:

[C++]

struct my_generator: public pseudo_generator<int>
{
    int,;
    int operator()();
};

int my_generator::operator()()
{
    BEGIN_GENERATOR2( s1, s2 );
    for 	
    END_GENERATOR;
    return -1; //dummy return;
};

[/C++]

SOmewhat more dirty, than Python, but significantly more clear than onriginal C++.


{ How it works }