The global context in Solidity

msg.sender, block.timestamp, block.number: the environment.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

// The globals: msg.sender, block.timestamp, block.number.
contract WorkbookStamp {
    struct Entry {
        address who;
        uint256 time;
        uint256 blockNo;
    }

    Entry[] public entries;

    function stamp() external {
        entries.push(Entry(msg.sender, block.timestamp, block.number));
    }

    function isRecent(uint256 i) external view returns (bool) {
        return block.timestamp - entries[i].time < 1 days;
    }
}

How it works

1. Every call carries its sender and the chain's clock.
2. block.timestamp is seconds; 1 days is sugar for 86400.
3. Stamps store the context for later comparison.

Keywords and builtins used here

• address
• bool
• contract
• external
• function
• public
• return
• returns
• struct
• uint256

The run, in numbers

Lines

21

Characters to type

438

Tokens

77

Three-star pace

60 tpm

At the three-star pace of 60 tokens a minute, this run takes about 77 seconds.

Type this snippet

Step 1 of 3 in The environment, step 21 of 28 in Language basics.

← Previous Next →