IELE should be evaluated.

[hypercube-lab]

The conceptual designs for IELE and HyperCube implement smart contracts from diametrically opposed perspectives. Everything has a gas price assigned to it in IELE, which is a generic Turing-complete programming language. An alternative to this is a spending plan, which is a very basic language in which every branch spends all of the bonded tokens and an implementation that does not need any memory allocations. In order to map spending plans to IELE, we'd need to consider a subset of stack-allocated programs where the gas price is extremely tiny and can be estimated in advance of the expenditure plan.

[agnitazudkll]

This new smart contract language is designed to resemble the concurrent smart contract valuation methodology. https://github.com/rchain/Rholang

[agnitazudkll]

If you're looking for interesting insights on the subject, you might want to take a look at Simplicity: A New Language for Blockchains by Russel O'Conner. Lua-like scripting is probably also required.
Abstract: https://arxiv.org/abs/1711.03028

This list also exposes many of the issues involved in devising smart contract language (see this devlist for example): https://www.reddit.com/r/bitcoin devlist/comments/79r1ma/simplicity an alternative to script russell/