// Chain Selection in dist_agent_lang
// This demonstrates how to choose and interact with different blockchains
@trust("hybrid")
@chain("ethereum")
@chain("polygon")
@chain("bsc")
@chain("arbitrum")
@chain("optimism")
@secure
service ChainSelectionExample {
// Chain-specific configurations (keys are chain_id as string for object literal compatibility)
active_chains: map<string, map<string, any>>;
default_chain: int = 1; // Ethereum Mainnet
// Cross-chain state
cross_chain_balances: map<string, map<int, int>>; // user => (chain_id => balance)
bridge_requests: map<string, map<string, any>>;
fn initialize() {
// Initialize with specific chains (object keys must be strings in DAL)
self.active_chains = {
"1": { // Ethereum Mainnet
"chain_id": 1,
"name": "Ethereum Mainnet",
"rpc_url": "https://mainnet.infura.io/v3/YOUR_PROJECT_ID",
"explorer": "https://etherscan.io",
"gas_limit": 21000,
"gas_price": 20, // gwei
"confirmations": 12
},
"137": { // Polygon
"chain_id": 137,
"name": "Polygon",
"rpc_url": "https://polygon-rpc.com",
"explorer": "https://polygonscan.com",
"gas_limit": 21000,
"gas_price": 30, // gwei
"confirmations": 256
},
"56": { // Binance Smart Chain
"chain_id": 56,
"name": "Binance Smart Chain",
"rpc_url": "https://bsc-dataseed.binance.org",
"explorer": "https://bscscan.com",
"gas_limit": 21000,
"gas_price": 5, // gwei
"confirmations": 15
},
"42161": { // Arbitrum
"chain_id": 42161,
"name": "Arbitrum One",
"rpc_url": "https://arb1.arbitrum.io/rpc",
"explorer": "https://arbiscan.io",
"gas_limit": 21000,
"gas_price": 0.1, // gwei
"confirmations": 1
},
"5": { // Ethereum Goerli
"chain_id": 5,
"name": "Ethereum Goerli",
"rpc_url": "https://goerli.infura.io/v3/YOUR_PROJECT_ID",
"explorer": "https://goerli.etherscan.io",
"gas_limit": 21000,
"gas_price": 2, // gwei
"confirmations": 6
}
};
log::info("chain", {
"event": "chains_initialized",
"chains_count": self.active_chains.size(),
"default_chain": self.default_chain
});
}
// Switch to a different chain
@txn
fn switch_chain(chain_id: int) -> bool {
let user = auth::session().user_id;
let old_chain = self.default_chain;
let chain_key = chain_id.to_string();
if (!self.active_chains.contains(chain_key)) {
log::error("chain", {
"event": "chain_not_supported",
"chain_id": chain_id,
"user": user
});
return false;
}
self.default_chain = chain_id;
log::audit("chain_switched", {
"user": user,
"old_chain": old_chain,
"new_chain": chain_id,
"chain_name": self.active_chains[chain_key]["name"]
});
log::info("chain", {
"event": "chain_switched",
"user": user,
"new_chain": self.active_chains[chain_key]["name"]
});
return true;
}
// Deploy contract to specific chain
@txn
fn deploy_to_chain(chain_id: int) -> string {
let chain_key = chain_id.to_string();
if (!self.active_chains.contains(chain_key)) {
log::error("chain", {
"event": "chain_not_supported",
"chain_id": chain_id
});
return "";
}
let chain_info = self.active_chains[chain_key];
// Use chain:: namespace to deploy
let contract_address = chain::deploy_contract(
chain_id,
"KEYS_Token",
{
"name": "KEYS Token",
"symbol": "KEYS",
"total_supply": 120000000
}
);
log::info("chain", {
"event": "contract_deployed",
"chain_name": chain_info["name"],
"contract_address": contract_address,
"chain_id": chain_id
});
return contract_address;
}
// Cross-chain transfer
@txn
@limit(15000)
fn cross_chain_transfer(
to_chain: int,
recipient: string,
amount: int
) -> bool {
let user = auth::session().user_id;
// Verify chains are supported
let to_chain_key = to_chain.to_string();
if (!self.active_chains.contains(to_chain_key)) {
log::error("chain", {
"event": "target_chain_not_supported",
"target_chain": to_chain,
"user": user
});
return false;
}
// Check balance on current chain
// let current_balance = self.cross_chain_balances[user][self.default_chain]
if (current_balance < amount) {
log::error("chain", {
"event": "insufficient_balance",
"user": user,
"current_balance": current_balance,
"required_amount": amount
});
return false;
}
// Create bridge request
let bridge_id = crypto::hash("bridge", user + "_" + self.default_chain + "_" + to_chain + "_" + amount);
self.bridge_requests[bridge_id] = {
"user": user,
"from_chain": self.default_chain,
"to_chain": to_chain,
"amount": amount,
"recipient": recipient,
"status": "pending",
"timestamp": chain::get_block_timestamp(self.default_chain)
};
// Deduct from current chain
if (!self.cross_chain_balances.contains(user)) {
self.cross_chain_balances[user] = {};
}
self.cross_chain_balances[user][self.default_chain] = current_balance - amount;
log::audit("cross_chain_transfer", {
"event": "transfer_initiated",
"user": user,
"from_chain": self.default_chain,
"to_chain": to_chain,
"amount": amount,
"bridge_id": bridge_id
});
log::info("chain", {
"event": "cross_chain_transfer_initiated",
"user": user,
"amount": amount,
"from_chain": self.default_chain,
"to_chain": to_chain
});
return true;
}
// Get gas estimate for a chain
fn estimate_gas(chain_id: int, operation: string) -> int {
if (!self.active_chains.contains(chain_id.to_string())) {
return 0;
}
// Use chain:: namespace to estimate gas
return chain::estimate_gas_cost(chain_id, operation);
}
// Get current gas price for a chain
fn get_gas_price(chain_id: int) -> float {
if (!self.active_chains.contains(chain_id.to_string())) {
return 0.0;
}
// Use chain:: namespace to get current gas price
return chain::get_current_gas_price(chain_id);
}
// Check transaction status across chains
fn get_transaction_status(chain_id: int, tx_hash: string) -> string {
if (!self.active_chains.contains(chain_id.to_string())) {
return "unknown";
}
// Use chain:: namespace to check transaction
return chain::get_transaction_status(chain_id, tx_hash);
}
}
// Chain selection helper functions
fn select_chain_by_criteria(criteria: map<string, any>) -> int {
// Criteria can include: speed, cost, security, ecosystem
let speed_priority = criteria.get("speed", "medium");
let cost_priority = criteria.get("cost", "medium");
let security_priority = criteria.get("security", "high");
if (speed_priority == "fast" && cost_priority == "low" && security_priority == "medium") {
return 137; // Polygon
} else if (speed_priority == "fast" && cost_priority == "low" && security_priority == "low") {
return 56; // BSC
} else if (speed_priority == "medium" && cost_priority == "medium" && security_priority == "high" ) {
return 1; // Ethereum
} else if (speed_priority == "fast" && cost_priority == "low" && security_priority == "high" ) {
return 42161; // Arbitrum
} else {
return 1; // Default to Ethereum
}
}
// Example usage
fn main() {
// Initialize chain selection example
let chain_example = ChainSelectionExample::new();
chain_example.initialize();
// Deploy to different chains
let eth_address = chain_example.deploy_to_chain(1);
let poly_address = chain_example.deploy_to_chain(137);
let bsc_address = chain_example.deploy_to_chain(56);
log::info("main", {
"event": "contracts_deployed",
"ethereum_address": eth_address,
"polygon_address": poly_address,
"bsc_address": bsc_address
});
// Switch to Polygon for lower gas fees
let switch_result = chain_example.switch_chain(137);
if (switch_result) {
log::info("main", {
"event": "chain_switched_successfully",
"new_chain": "Polygon"
});
}
// Perform cross-chain transfer
let transfer_result = chain_example.cross_chain_transfer(1, "0x1234...", 1000);
if (transfer_result) {
log::info("main", {
"amount": 1000,
"to_chain": 1
});
}
// Get gas estimates
let eth_gas = chain_example.estimate_gas(1, "transfer");
let poly_gas = chain_example.estimate_gas(137, "transfer");
log::info("main", {
"event": "gas_estimates_retrieved",
"ethereum_gas": eth_gas,
"polygon_gas": poly_gas
});
// Select chain based on criteria
let optimal_chain = select_chain_by_criteria({
"speed": "fast",
"cost": "low",
"security": "medium"
});
log::info("main", {
"event": "optimal_chain_selected",
"chain_id": optimal_chain,
"criteria": {
"speed": "fast",
"cost": "low",
"security": "medium"
}
});
log::info("main", {
"event": "chain_selection_demo_completed",
"status": "success"
});
}