A long-standing proposal to bring “smarter” smart contracts to bitcoin’s main net has just taken one step closer to implementation.

Developers have submitted a pull request for Merkelized Abstract Syntax Trees (MAST), marking the first time this smart contracts proposal has been the subject of a pull request seeking its integration into bitcoin’s code.

The pull request combines pay-to-script-hash (P2SH) with MERKLE-BRANCH-VERIFY, allowing users to define how payments would occur. As previously reported by CoinDesk, these two features, combined with a third Bitcoin Improvement Proposal (BIP) called “Tail Call Execution Semantics,” would allow users to create private smart contracts on the bitcoin network.

These private smart contracts would allow users to define their own criteria by which a payment would process, enabling multiple factors to be considered by the program. The smart contracts would then execute on their own.

The combination of BIPs would also allow for these smart contracts to be stored in a compact manner on the actual bitcoin blockchain, meaning they would not take up a large amount of block space, or the amount of data that can be stored within each block of transactions.

If developers and the broader bitcoin community approve of the change, it could be added to bitcoin by way of a soft fork.