In this lesson, you will:

• Learn how Solidity's import directive functions and how it differs from other languages.
• Explore the different types of imports in Solidity.

Solidity uses the import directive to include code from other files, similar to JavaScript imports. This feature allows you to incorporate constants, structs, enums, events, functions, and contracts from external files. Unlike JavaScript, Solidity doesn’t have an export statement or default export.

Import Directive:

In Solidity, the import directive is used to integrate other Solidity files into your contract. For instance, importing the Solana library lets you utilize its methods within your Solidity contracts. Solidity's approach to imports is somewhat akin to JavaScript's ES6, with some differences.

Example:

import { foo, bar } from "defines.sol";

In Solidity, import is hoisted, allowing foo and bar to be accessible before the import statement.

Types of Imports:

There are several types of imports you can use:

1. Import Everything from a Library:

 import "defines.sol";

This imports all items from "defines.sol", differing from ES6 where such syntax imports nothing.

2. Select Specific Items from a Library:

 import { foo, bar } from "defines.sol";

Only imports foo and bar from "defines.sol".

3. Using Import Maps: Import maps link a path segment to a specific location on the file system. For example:

 import map @openzeppelin=/opt/openzeppelin-contracts/contracts
 import "@openzeppelin/interfaces/IERC20.sol";

This would link to /opt/openzeppelin-contracts/contracts/interfaces/IERC20.sol.

You can also rename imports for convenience or to avoid name clashes:

import { bar as baz, foo } from "defines.sol";

This renames bar to baz from "defines.sol".

Grouping Imports Under a Namespace:

import "defines.sol" as defs;
// Now use defs.bar, defs.foo, etc.

This groups all imports from "defines.sol" under the defs namespace.

Next, we'll delve into pragma directives in Solidity,

an essential aspect of setting up your Solidity environment for Solana programming. Pragma directives dictate compiler behaviour and compatibility, ensuring your code is interpreted correctly.