Implement AMM 2.0-light

CODEOWNERS

@@ -11,6 +11,7 @@
 /zrml/authorized/ @Chralt98
 /zrml/court/ @Chralt98
 /zrml/global-disputes/ @Chralt98
+/zrml/neo-swaps/ @maltekliemann
 /zrml/prediction-markets/ @maltekliemann
 /zrml/rikiddo/ @sea212
 /zrml/simple-disputes/ @Chralt98
@@ -19,4 +20,4 @@
 
 # Skip weight and Cargo.toml files
 **/weights.rs
-**/Cargo.toml
+**/Cargo.toml

Cargo.toml

@@ -10,6 +10,7 @@ default-members = [
     "zrml/global-disputes",
     "zrml/liquidity-mining",
     "zrml/market-commons",
+    "zrml/neo-swaps",
     "zrml/orderbook-v1",
     "zrml/prediction-markets",
     "zrml/prediction-markets/runtime-api",
@@ -31,6 +32,7 @@ members = [
     "zrml/global-disputes",
     "zrml/liquidity-mining",
     "zrml/market-commons",
+    "zrml/neo-swaps",
     "zrml/orderbook-v1",
     "zrml/orderbook-v1/fuzz",
     "zrml/prediction-markets",
@@ -229,6 +231,7 @@ zrml-court = { path = "zrml/court", default-features = false }
 zrml-global-disputes = { path = "zrml/global-disputes", default-features = false }
 zrml-liquidity-mining = { path = "zrml/liquidity-mining", default-features = false }
 zrml-market-commons = { path = "zrml/market-commons", default-features = false }
+zrml-neo-swaps = { path = "zrml/neo-swaps", default-features = false }
 zrml-orderbook-v1 = { path = "zrml/orderbook-v1", default-features = false }
 zrml-prediction-markets = { path = "zrml/prediction-markets", default-features = false }
 zrml-prediction-markets-runtime-api = { path = "zrml/prediction-markets/runtime-api", default-features = false }
@@ -250,6 +253,9 @@ url = "2.2.2"
 arbitrary = { version = "1.3.0", default-features = false }
 arrayvec = { version = "0.7.4", default-features = false }
 cfg-if = { version = "1.0.0" }
+fixed = { version = "=1.15.0", default-features = false, features = ["num-traits"] }
+# Using math code directly from the HydraDX node repository as https://github.com/galacticcouncil/hydradx-math is outdated and has been archived in May 2023.
+hydra-dx-math = { git = "https://github.com/galacticcouncil/HydraDX-node", package = "hydra-dx-math", tag = "v18.0.0", default-features = false }
 # Hashbrown works in no_std by default and default features are used in Rikiddo
 hashbrown = { version = "0.12.3", default-features = true }
 hex-literal = { version = "0.3.4", default-features = false }
@@ -258,6 +264,7 @@ num-traits = { version = "0.2.15", default-features = false }
 rand = { version = "0.8.5", default-features = false }
 rand_chacha = { version = "0.3.1", default-features = false }
 serde = { version = "1.0.152", default-features = false }
+typenum = { version = "1.15.0", default-features = false }
 
 [profile.dev.package]
 blake2 = { opt-level = 3 }

README.md

@@ -4,15 +4,18 @@
 
 # Zeitgeist: An Evolving Blockchain for Prediction Markets and Futarchy
 
-![Rust](https://github.com/zeitgeistpm/zeitgeist/workflows/Rust/badge.svg) [![Codecov](https://codecov.io/gh/zeitgeistpm/zeitgeist/branch/main/graph/badge.svg)](https://codecov.io/gh/zeitgeistpm/zeitgeist) [![Discord](https://img.shields.io/badge/discord-https%3A%2F%2Fdiscord.gg%2FMD3TbH3ctv-purple)](https://discord.gg/MD3TbH3ctv) [![Telegram](https://img.shields.io/badge/telegram-https%3A%2F%2Ft.me%2Fzeitgeist__official-blue)](https://t.me/zeitgeist_official)
+![Rust](https://github.com/zeitgeistpm/zeitgeist/workflows/Rust/badge.svg)
+[![Codecov](https://codecov.io/gh/zeitgeistpm/zeitgeist/branch/main/graph/badge.svg)](https://codecov.io/gh/zeitgeistpm/zeitgeist)
+[![Discord](https://img.shields.io/badge/discord-https%3A%2F%2Fdiscord.gg%2FMD3TbH3ctv-purple)](https://discord.gg/MD3TbH3ctv)
+[![Telegram](https://img.shields.io/badge/telegram-https%3A%2F%2Ft.me%2Fzeitgeist__official-blue)](https://t.me/zeitgeist_official)
 
 Zeitgeist is a decentralized network for creating, betting on, and resolving
 prediction markets. The platform's native currency, the ZTG, is used to sway the
 direction of the network, and as a means of last-call dispute resolution.
 Additionally, Zeitgeist is a protocol for efficient trading of prediction market
 shares and will one day become the backbone of the decentralized finance
-ecosystem by allowing traders to create complex financial contracts on
-virtually _anything_.
+ecosystem by allowing traders to create complex financial contracts on virtually
+_anything_.
 
 ## Modules
 
@@ -27,6 +30,9 @@ virtually _anything_.
   liquidity to swap pools.
 - [market-commons](./zrml/market-commons) - Contains common operations on
   markets that are used by multiple pallets.
+- [neo-swaps](./zrml/neo-swaps) - An implementation of the Logarithmic Market
+  Scoring Rule as constant function market maker, tailor-made for decentralized
+  combinatorial markets and Futarchy.
 - [orderbook-v1](./zrml/orderbook-v1) - A naive orderbook implementation that's
   only part of Zeitgeist's PoC. Will be replaced by a v2 orderbook that uses
   0x-style hybrid on-chain and off-chain trading.

docs/changelog_for_devs.md

@@ -12,6 +12,38 @@ As of 0.3.9, the changelog's format is based on
 components which query the chain's storage, the extrinsics or the runtime
 APIs/RPC interface.
 
+## v0.4.1
+
+### Added
+
+- Implement AMM-2.0-light in the form of zrml-neo-swaps. The new pallet has the
+  following dispatchables:
+
+  - `buy`: Buy outcome tokens from the specified market.
+  - `sell`: Sell outcome tokens to the specified market.
+  - `join`: Join the liquidity pool for the specified market.
+  - `exit`: Exit the liquidity pool for the specified market.
+  - `withdraw_fees`: Withdraw swap fees from the specified market.
+  - `deploy_pool`: Deploy a pool for the specified market and provide liquidity.
+
+  The new pallet has the following events:
+
+  - `BuyExecuted { who, market_id, asset_out, amount_in, amount_out, swap_fee_amount, external_fee_amount }`:
+    Informant bought a position.
+  - `SellExecuted { who, market_id, asset_in, amount_in, amount_out, swap_fee_amount, external_fee_amount }`:
+    Informants sold a position.
+  - `FeesWithdrawn { who }`: Liquidity provider withdrew fees.
+  - `JoinExecuted { who, market_id, pool_shares_amount, amounts_in, new_liquidity_parameter }`:
+    Liquidity provider joined the pool.
+  - `ExitExecuted { who, market_id, pool_shares_amount, amounts_out, new_liquidity_parameter }`:
+    Liquidity provider left the pool.
+  - `PoolDeployed { who, market_id, pool_shares_amount, amounts_in, liquidity_parameter }`:
+    Pool was created.
+  - `PoolDestroyed { who, market_id, pool_shares_amount, amounts_out }`: Pool
+    was destroyed.
+
+  For details, please refer to the `README.md` and the in-file documentation.
+
 ## v0.4.0
 
 [#976]: https://github.com/zeitgeistpm/zeitgeist/pull/976

primitives/Cargo.toml

@@ -1,5 +1,6 @@
 [dependencies]
 arbitrary = { workspace = true, optional = true }
+fixed = { workspace = true }
 frame-support = { workspace = true }
 frame-system = { workspace = true }
 orml-currencies = { workspace = true }
@@ -13,7 +14,9 @@ sp-core = { workspace = true }
 sp-runtime = { workspace = true }
 
 [dev-dependencies]
+more-asserts = { workspace = true }
 test-case = { workspace = true }
+typenum = { workspace = true }
 
 [features]
 default = ["std"]

primitives/src/constants.rs

@@ -37,7 +37,8 @@ pub const BLOCKS_PER_MINUTE: BlockNumber = 60_000 / (MILLISECS_PER_BLOCK as Bloc
 pub const BLOCKS_PER_HOUR: BlockNumber = BLOCKS_PER_MINUTE * 60; // 300
 
 // Definitions for currency
-pub const BASE: u128 = 10_000_000_000;
+pub const DECIMALS: u8 = 10;
+pub const BASE: u128 = 10u128.pow(DECIMALS as u32);
 pub const CENT: Balance = BASE / 100; // 100_000_000
 pub const MILLI: Balance = CENT / 10; //  10_000_000
 pub const MICRO: Balance = MILLI / 1000; // 10_000
@@ -82,6 +83,9 @@ pub const GLOBAL_DISPUTES_LOCK_ID: [u8; 8] = *b"zge/gdlk";
 /// Pallet identifier, mainly used for named balance reserves.
 pub const LM_PALLET_ID: PalletId = PalletId(*b"zge/lymg");
 
+// NeoSwaps
+pub const NS_PALLET_ID: PalletId = PalletId(*b"zge/neos");
+
 // Prediction Markets
 /// The maximum allowed market life time, measured in blocks.
 pub const MAX_MARKET_LIFETIME: BlockNumber = 4 * BLOCKS_PER_YEAR;

primitives/src/constants/mock.rs

@@ -70,6 +70,13 @@ parameter_types! {
     pub const LiquidityMiningPalletId: PalletId = PalletId(*b"zge/lymg");
 }
 
+// NeoSwaps
+parameter_types! {
+    pub storage NeoExitFee: Balance = CENT;
+    pub const NeoMaxSwapFee: Balance = 10 * CENT;
+    pub const NeoSwapsPalletId: PalletId = PalletId(*b"zge/neos");
+}
+
 // Prediction Market parameters
 parameter_types! {
     pub const AdvisoryBond: Balance = 25 * CENT;
@@ -146,11 +153,10 @@ parameter_types! {
 }
 
 parameter_type_with_key! {
-    // Well, not every asset is a currency ¯\_(ツ)_/¯
     pub ExistentialDeposits: |currency_id: CurrencyId| -> Balance {
         match currency_id {
             Asset::Ztg => ExistentialDeposit::get(),
-            _ => 0
+            _ => 10
         }
     };
 }

primitives/src/lib.rs

@@ -1,3 +1,4 @@
+// Copyright 2023 Forecasting Technologies LTD.
 // Copyright 2021-2022 Zeitgeist PM LLC.
 //
 // This file is part of Zeitgeist.
@@ -22,6 +23,7 @@ extern crate alloc;
 mod asset;
 pub mod constants;
 mod market;
+pub mod math;
 mod max_runtime_usize;
 mod outcome_report;
 mod pool;