# Integrate a complex Swift Package into your iOS app

In this blog post I help app developers to understand the terminology of a Swift Package and how to integrate a more complex structured Swift Package in an iOS application.

The simplest package structure, created by the `swift package init` command, consists of
- a package
  - with a single product (type: library)
    - using a single target (+ a test target)

The names of all those package/product/target is identical.

Let's look at a more complex example:

```Swift
// swift-tools-version: 5.6
import PackageDescription

let package = Package(
    name: "Package2",
    products: [
        .library(name: "Package2LibA", targets: ["Package2TargetA"]),
        .library(name: "Package2LibB", targets: ["Package2TargetB"]),
    ],
    dependencies: [
        .package(path: "../Package1"),
    ],
    targets: [
        .target(
            name: "Package2TargetA",
            dependencies: [.product(name: "Package1Lib", package: "Package1")]),
        .target(
            name: "Package2TargetB",
            dependencies: [.product(name: "Package1Lib", package: "Package1")])
        )
    ]
)
```

This package (named `Package2` here) offers two *library* products. Each product has its own target. Each target makes use of a library offered by a package dependency.

Let me start explaining the different building blocks from the view of an *app developer*.

- You want to use functionality from a package => **you add the *package* to your Xcode project**.

![You add a package to your Xcode project](https://cdn.hashnode.com/res/hashnode/image/upload/v1647983531206/JbGhuTEUg.png)

- You want to use a library => **you add a library *product* to your app target in Xcode**.

  ![You add a library to your Xcode target](https://cdn.hashnode.com/res/hashnode/image/upload/v1647983547643/WsrfMJHBS.png)

- Finally, when importing related code from the library => **you are using the `import <target/module>` statement**. 

  ![You use import statement for modules](https://cdn.hashnode.com/res/hashnode/image/upload/v1647983572206/CBOYAeocU.png)

  In this example the module `Package2TargetB` offers a public struct `API_B`.

> A Swift target is pretty much equal to a Swift module, so they are often used interchangeably. A module specifies a namespace and enforces access controls on which parts of that code can be used outside of the module.

I highly recommend reading the definition given by Jeremy David Giesbrecht in the [Swift Forum](https://forums.swift.org/t/module-vs-product-vs-target/27640/2). It speaks more to package developers.