Library using-for directive

Why use this example

Use this pattern to test contract composition, external calls, events, and return values inside one reproducible run. The entry isolates library using-for directive so its input, result, and state changes stay easy to compare.

Solidity to run

library UintMath {
  function squared(uint256 self) internal pure returns (uint256) {
    return self * self;
  }
}
contract Calculator {
  using UintMath for uint256;
  function square(uint256 value) external pure returns (uint256) {
    return value.squared();
  }
}

Calculator calculator = new Calculator()
calculator.square(7)

Official Solidity reference

Compare this focused investigation with the complete language definition in the Solidity documentation.

What to expect

The using-for directive exposes squared as a uint256 member and the contract returns 49.

Continue the investigation

Change a value, add another expression, or open Inspect after the run. Accepted entries remain available to the next entry, and the clean replay keeps the complete result reproducible.