Contract Implementation Example of IChronicle

info

You can find an example of our IChronicle.sol interface here . Please see the comments corresponding to each function to better understand the utility it provides.

Example Contract

The Example contract is a basic implementation of the IChronicle interface. It demonstrates basic interaction with an oracle interface defined by IChronicle. The contract has no protections, and should only be used for learning purposes.

Key Features

1. State Variables:

_val: Stores the current value from the oracle.

_age: Stores the age of the value.

2. Immutable Variables:

wat: A public immutable variable set during contract deployment that represents the Oracle's identifier.

3. Functions:

read(): Returns the current value of the Oracle stored in _val.

tryRead(): Checks if _val is non-zero and returns a tuple with a boolean result and the value of _val. If _val is non-zero, it returns (true, val); otherwise, it returns (false, val).

readWithAge(): Retrieves the values of _val and _age, checks that _val is non-zero, and returns a tuple with these two values. If _val is zero, the function call will fail, and no values will be returned.

tryReadWithAge(): Checks if _val is non-zero and returns a tuple indicating the result of this check along with the values of _val and _age (or zeros if _val is zero).

poke(): Allows an external caller to update the values of the state variables _val and _age. This function can be used to set or change the Oracle's value and its age.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.16;

import {IChronicle} from "chronicle-std/IChronicle.sol";

// This contract has ZERO protections, never use for anything other than learning!
contract Example is IChronicle {
    uint private _val;
    uint32 private _age;

    /// @inheritdoc IChronicle
    /// The Oracle identifier; mostly asset pairs, e.g. ETH/USD
    bytes32 public immutable wat;

    constructor(bytes32 _wat) {
          wat = _wat;        
    }

    /// @inheritdoc IChronicle
    function read() external view returns (uint) {
          return _val;
    }

    /// @inheritdoc IChronicle
    function tryRead() external view returns (bool, uint) {
        uint val = _val;
        return (val != 0, val);
    }

    /// @inheritdoc IChronicle
    /// @return value The oracle's current value.
    /// @return age The value's age.
    function readWithAge() external view returns (uint, uint) {
        uint val = _val;
        uint age = _age;
        require(val != 0);
        return (val, age);
    }

    /// @inheritdoc IChronicle
    function tryReadWithAge() external view returns (bool, uint, uint)
    {
        uint val = _val;
        uint age = _age;
        return val != 0 ? (true, val, age) : (false, 0, 0);
    }

    function poke(uint val, uint32 age) external {
        _val = val;
        _age = age;
    }
}