Gremlins in a high-level language for blockchain development.
Like Solidity: it compiles a high-level language to EVM bytecode.
Unlike Solidity: it is not for writing contracts, but instead for
querying on-chain data, synchronously with eth_call, with arbitrary logic
to return JavaScript-friendly results.
TL;DR: Like a more nuanced multicall for read-only operations
- Tiny; under 8kb for parser, compiler and code generator (16kb uncompessed)
- Zero dependencies
- Easy to use, with a TypeScript-inspired syntax
- Aggregates many operations together
- Providers synchronous access to blockchain data
- Open Source; 100% MIT licensed
MyAllowance.gizmo
/**
* Example: determine the current *actual* allowance of
* DAI for many addresses.
*
* If a token has an infinite allowance, but the sender
* only has 4 DAI, the actual balance is 4 DAI, as that
* is all that would successfuly be transferable.
*/
interface Erc20 {
balanceOf(address): uint;
allowance(address): uint
}
function min(a: uint, b: uint): uint {
if (a < b) { return a; }
return b;
}
function main(sender: address, addresses: Array<address>) {
const dai = <Erc20>0x6B175474E89094C44Da98b954EedeAC495271d0F;
const result: Array<uint> = [ ];
for (const address of addresses) {
const balance = dai.balanceOf(address);
const allowance = dai.allowance(addess, sender);
result.push(min(balance, allowance));
}
}Using:
const code = fs.readFileSync("MyAllowance.gizmo");
// Who the allowance permissions are being requested for
const sender = // who the allowances permit
// The addresses to query
const address = [
// ...
];
const allowances: Array<bigint> = gremlins.eval(code, sender, addresses);MIT Licesnse.