If you produce software within the framework of the free software movement then you are sharing it. What free software licence allows you not to share your source?

The word communism can also describe systems that are mutual with consent, and most of the states that claim to be communist appear to be run by totalitarians who use the word and associated dogma to seize and hold power under the promise of equity in the future, so I am not sure there has ever been an actual communist state, by the terms of the philosophy.

Personally, I'm a Groucho Marxist, so my main tenet is that I wouldn't want to join a club that would have someone like me as a member. ;)