Example Contracts

Overview

The contracts/ directory contains production-ready reference implementations covering DeFi primitives, oracles, cross-chain messaging, and utilities. All contracts are written in Zig using the Ashen SDK.

Tokens

SFT Token (sft_v1) — Rust

A feature-rich fungible token with modular capabilities:

• Core: mint, burn, transfer
• Roles: owner, minter, blacklister, fee manager
• Allowances: approve/transferFrom pattern
• Blacklist: address blocking
• Fees: configurable transfer fees
• Recovery: owner can recover stuck tokens

Optional features (compile-time): pause, whitelist, limits, locking, snapshots, governance, multisig, flash loans, compliance hooks.

# Build with default features
just contract-build --manifest-path contracts/sft_v1/Cargo.toml

# Build with all features
cargo build --manifest-path contracts/sft_v1/Cargo.toml --features full

Key functions: mint, burn, transfer, approve, transfer_from, set_fee

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DeFi Primitives

AMM Pool (amm_pool_v1)

A constant-product automated market maker (x × y = k) with:

• 0.3% default fee (configurable by owner)
• K-invariant verification using u256 arithmetic
• Slippage protection and minimum output checks

# Build
cd contracts/amm_pool_v1 && zig build -Doptimize=ReleaseSmall

Key functions: swap_x_for_y, swap_y_for_x, add_liquidity, remove_liquidity

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Concentrated Liquidity (concentrated_liquidity_v1)

Bin-based fixed-price liquidity pool (similar to Trader Joe v2):

• Discrete price bins with configurable bin step
• Capital-efficient concentrated positions
• Active bin tracking for swaps

Key functions: add_liquidity, remove_liquidity, swap, get_active_bin

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Stable Swap (stable_swap_v1)

StableSwap invariant AMM optimized for pegged assets:

• Low slippage for like-kind swaps
• Configurable amplification coefficient
• Multi-asset support

Key functions: exchange, add_liquidity, remove_liquidity, get_dy

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Order Book (order_book_v1)

Central limit order book (CLOB) with price-time priority:

• Sorted storage keys for efficient bid/ask iteration
• Partial fills and order cancellation
• Market and limit order types

Key functions: place_order, cancel_order, match_orders, get_best_bid, get_best_ask

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DEX Router (dex_router_v1)

Multi-hop swap router demonstrating cross-contract calls:

• Chained swaps across multiple pools
• Access list hints for state key warming
• Slippage protection across the full path

Key functions: swap_exact_in, swap_exact_out, get_amounts_out

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Lending Market (lending_market_v1)

Single-asset money market with:

• Supply/withdraw with share-based accounting
• Borrow/repay with interest accrual
• Liquidation with configurable thresholds

Key functions: supply, withdraw, borrow, repay, liquidate

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Vault (vault_v1 / vault_strategy_v1)

ERC-4626 style tokenized vault:

• Deposit/withdraw with share accounting
• Pluggable yield strategies
• Performance fee collection

Key functions: deposit, withdraw, harvest, report

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Staking (stake_pool_v1 / reward_gauge_v1)

Staking and rewards distribution:

• Time-weighted reward accumulation
• Multiple reward tokens
• Gauge voting for emissions

Key functions: stake, unstake, claim_rewards, vote

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Governance (timelock_governor_v1)

On-chain governance with timelock:

• Proposal creation and voting
• Configurable voting period and quorum
• Timelock delay for execution

Key functions: propose, vote, queue, execute

Oracles

Price Oracle (price_oracle_v1)

Push/pull price oracle with TWAP:

• Signed price updates from authorized publishers
• Circular buffer for time-weighted averaging
• Staleness checks

Key functions: update_price, get_price, get_twap

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Pyth Oracle (pyth_oracle_v1)

Pyth-style ed25519 price attestation verification:

• Publisher set management with threshold
• Direct signature verification (not via Wormhole)
• Price confidence intervals

Key functions: verify_attestation, update_publisher_set, get_price

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RedStone Oracle (redstone_oracle_v1)

RedStone data package verification:

• ECDSA signature verification
• Multi-signer threshold support
• Timestamp validation

Key functions: verify_data_package, get_price

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Chainlink OCR2 (chainlink_ocr2_v1)

Chainlink Off-Chain Reporting v2 verification:

• Multi-signature report verification
• Configurable signer set
• Report decoding

Key functions: verify_report, set_config, latest_answer

Cross-Chain

Wormhole Core (wormhole_core_v1)

Wormhole VAA (Verified Action Approval) verification:

• Guardian signature verification
• Message parsing and validation
• Replay protection

Key functions: verify_vaa, parse_vaa, update_guardian_set

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Axelar GMP (axelar_gmp_v1)

Axelar General Message Passing:

• Cross-chain message execution
• Operator set management
• Batch processing

Key functions: execute, initialize, update_operators

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Hyperlane ISM (hyperlane_ism_v1)

Hyperlane Interchain Security Module:

• Validator-based message verification
• Configurable threshold per origin
• Message routing

Key functions: verify_message, update_validator_set

Infrastructure

Light Client (light_client_v1)

On-chain light client for finality verification:

• MMR (Merkle Mountain Range) proof verification
• BLS signature aggregation
• Header chain validation

Key functions: verify_finality_proof, update_header, get_root

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Fee Sponsor (fee_sponsor_v1)

Third-party gas sponsorship:

• Sponsor agreements with spending limits
• Per-user and per-contract policies
• Expiration and revocation

Key functions: create_agreement, sponsor_tx, revoke, withdraw

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Source Registry (source_registry_v1)

Contract source code registry:

• On-chain source verification
• Version management
• Metadata storage

Key functions: register, verify, get_source

Testing & Development

Mock Pool (mock_pool_v1)

Deterministic AMM for testing:

• Configurable reserves and fees
• Predictable swap outputs
• DEX router integration testing

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Gas Burner (gas_burner_v1)

Gas throughput stress testing:

• Pure compute workload (ALU-heavy)
• Storage-write workload
• Mixed DeFi-like operations
• Parallel execution testing

# Run stress test
just gas-stress --scenario mixed --duration 60

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Zig Fixture (zig_fixture)

Minimal contract template for testing the SDK and toolchain.

Building Contracts

All Zig contracts follow the same build pattern:

# Build a single contract
cd contracts/<name> && zig build -Doptimize=ReleaseSmall

# Build all contracts
just contract-build-all

Contract Structure

Each contract directory contains:

contracts/<name>/
├── build.zig          # Build configuration
├── linker.ld          # Linker script for RISC-V
├── src/
│   └── main.zig       # Contract implementation
└── zig-out/           # Build output (gitignored)

Reference Implementation

For a complete, well-documented example, see amm_pool_v1 which demonstrates:

• Full SDK usage (storage, events, math, guards)
• Proper error handling
• Gas-efficient patterns
• Comprehensive testing