Today we’re excited to share the first release of our open source desktop app for our Rainlang powered DEX protocol, imaginatively named Raindex.

Raindex allows anyone to write, deploy and manage perpetual token trading strategies, written in Rainlang, on any EVM network.

We’ve also created an extension to Rainlang, available only on the Flare network, that allows any strategy writer to use the Flare Time Series Oracles (FTSOs) directly within their strategies.

The culmination of three years of dedicated development, the Raindex app gives you the flexibility and power usually associated with CEX trading or running bots, whilst retaining the attributes we’re all here for - it’s trustless, permissionless and decentralised. It empowers users to craft and execute Rainlang strategies without intermediaries, blending the best of both worlds.

How does this look in practice?

1. Express what you want by writing a strategy in Rainlang
2. Deposit your tokens into vaults and deploy your order
3. Sit back and relax - fillers compete for your order flow

This is a totally new kind of DEX, where traders can move past "one size fits all" AMM curves and be given total freedom in how they express their trades. It’s also completely onchain, which means users don’t need to put their funds in someone else’s hands or put their hot wallet private keys in a bot connected to the internet.

This is a community launch, so for now the contracts are unaudited. Use at your own risk and as always, please DYOR.

The app​

What can you do with the app?

As of today you can use the app to:

• Write, save and load strategies via the .rain file format
• Run monte carlo modelling and produce charts
• Deploy your strategies
• Deposit and withdraw into your vaults
• Get real-time updates on your strategies’ progress

There’s a few layers of the stack that have come together to make this happen:

• Rainlang, a new smart contract language that is itself parsed and interpreted onchain by smart contracts
• The Raindex smart contracts and protocol - this includes everything onchain as well as the fillers who actually execute orders
• Finally, the Raindex app - a fully self-hosted way to write Rainlang and interact with the protocol with no intermediaries

We see Rainlang and Raindex going far and wide, but it’s early days and therefore our first users are early adopters. For now, what does a Raindex user look like?

• They aren’t afraid of a learning curve and enjoy taking responsibility for their onchain activities if it means more security and utility
• They are inherently creative, and they’ll think of ideas for this that we haven’t
• They want to run trading or market making strategies over time, but don’t want to run any infra or bots of their own
• They value decentralisation and want to do all of the above trustlessly and non-custodially
• They join us in Telegram to share experiences so we can all learn and improve Rain together

What is Rainlang?​

Rainlang is the native language of DeFi. If you can write an Excel formula, we think you can learn to write Rainlang.

Rainlang is:

• Parsed & interpreted onchain (by a smart contract)
• Permissionlessly extensible (add your own words to the language)
• Immutable (none of the contracts are upgradable or have admin keys)

using-words-from flare-sub-parser

/* ensure that the cooldown time has elapsed since the last trade */
:ensure(
  greater-than-or-equal-to(
    block-timestamp()
    int-add(get("last-traded") 43200) /* 12 hrs in seconds */
  )
),

/* getting a quote from the Flare FTSO */
max-output: 100e18,
price: ftso-current-price-pair(‘USD’ ‘WFLR’ 3600),

:set("last-traded" block-timestamp());

The above Raindex order buys $100 worth of WFLR every 12 hours, at the current price returned by the Flare Time Series Oracle (FTSO). If you don’t think you could’ve written it yourself, at the very least you can probably understand it and maybe even tweak it to suit your purposes.

What other kinds of strategies can you run? Pretty much anything you can imagine… That said, we have a few ideas:

• Other flavours of Dollar cost averaging (DCA):
• Stop loss
• Dutch orders
• Portfolio rebalancing
• Market making and liquidity management
• Trend tracking trading strategies

Flare deployment and the Flare Time Series Oracles (FTSOs)​

As you may have noticed in the example above, we’re using the Flare FTSOs to make sure our order is always offering the up-to-date market price for FLR. This is a subparser available only on Flare and an example of new words can be added to Rainlang, totally permissionlessly. We’ll be further extending this subparser with new words for EMAs, bringing even more power to those writing strategies with Raindex.

Why is this cool? Flare offers a unique trust model for the oracles on their network as the data availability and integrity is provided by the validators themselves. Raindex exposes these oracles directly to traders, without needing devs.

The Flare FTSO words are not only available in Raindex, but anywhere Rainlang is being used. Anybody building DeFi products with Rainlang can use these words.

Getting started​

If you’d like to get started, check out our first videos, where you can learn how to deploy your first strategy.

If you need support or have any questions, @thedavidmeister, @dcatki or @highonhopium are always in the community Telegram group.

Today we merged the standalone version of the interpreter which ships as a mere interface from the perspective of the calling contract. New words added and significant changes to Flow usage and security model.

I've been working on converting all the interpreter work into an interface that can support standalone interpreter contracts. This will bring several benefits:

• Upgradeability by using newer interpreters in old contracts
• Smaller code size for contracts that use interpreters
• Ability to provide more opcodes in the interpreter contract
• Ability to support third party interpreters that match the interface

Let’s start with something basic. The first game currency we want to build has just a max supply. We could write that without even using the expression engine.

Introduction​

Josh has been working on a brainscan v0.0 where we we show an expression, written into a simple contract, in this case ERC20 emissions which is powered by the Rain interpreter.

The expression is written in Rain script, a spreadsheet like expression writer. A simulation runs real time to tell you the rules for the wallet connected to the site and the expression is deployable using the Deploy Emissions ERC20 button when ready.

I don't think it is immediately clear at all what it means or why it is good to have a "rain interpreter".

The EVM already has general purpose set of opcodes for smart contracts, why do we want to reinvent that wheel?

How is a Rain interpreter different to the myriad of languages like solidity, vyper, etc. that are high level, battle tested and compile to the EVM?

How can this possibly be gas efficient, useful, secure, etc.?

Everything that Rain can possibly do could be coded in Solidity (the Rain interpreter itself is Solidity) so what's the point?

As the Flow contracts progress through the QA process and test coverage improves, we can start to talk about things to do with Flow.

Yes there's all the marketplace, escrow, sale, mint type stuff you'd expect.

Maybe we can do something a little different and fun too?

One of the ongoing experiments we've been working on in our collective is a Rain-powered asset designer and marketplace. At the moment it's a "game designer" but in reality this could be applied to any kind of marketplace-as-gamified-economy.

Due to popular demand, I've recorded a demo of how you could use the Game Designer POC to quickly create a system of game assets, where the economy itself could be considered a game.

This week I spent some time on a general purpose struct that defines token movements. In the near future this struct and associated logic will replace the EmissionsERC20 contract.

This is all a leadup to "adminless upgrades" for interpreters (previously known as VMs) that I'll try to get working "soon".

In short, this is the crux of the flow code in Solidity from this week.

This post is synthesised from conversations with the Game7 DAO during their grants process.

Describe the problem that your potential users are facing today.​

Game economies are struggling to break the 1-2 token paradigm and so the ‘play-to-earn’ movement is being revisited with people not sure what will drive the next waves of adoption from web2 to web3 gaming.