DependencyGraph

A lightweight, type‑safe library for modeling and resolving directed acyclic graphs (DAGs) of dependencies. It provides a simple API to define nodes, establish relationships, and automatically compute an execution order that respects all dependencies.

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Features

• Declarative DAG construction – define nodes and edges with minimal boilerplate.
• Automatic topological sorting – get a valid execution order out of the box.
• Cycle detection – early validation to prevent invalid graphs.
• Generic typing – works with any hashable key type (String, Int, custom structs, etc.).
• Zero‑dependency – pure Swift, no external library overhead.
• Testable – comprehensive unit‑test suite included.

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Installation

Swift Package Manager

Add the package to your Package.swift:

// swift-tools-version: 5.9
import PackageDescription

let package = Package(
    name: "MyPackage",
    dependencies: [
        .package(url: "https://github.com/P0rc3lain/DependencyGraph.git", from: "0.1.0"),
    ],
    targets: [
        .executableTarget(
            name: "MyExecutable",
            dependencies: ["DependencyGraph", "MyPackage"]),
    ]
)

Then run:

swift build

Xcode

1. Open your project.
2. Choose File → Swift Packages → Add Package Dependency….
3. Enter the URL https://github.com/P0rc3lain/DependencyGraph.git and select the desired version.
4. Add the library target to your target’s Dependencies.

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Usage

import DependencyGraph

// 1️⃣ Define nodes (any hashable type)
let graph = PNGraph()
let a = graph.add(identifier: "A")
let b = graph.add(identifier: "B")
let c = graph.add(identifier: "C")
let d = graph.add(identifier: "D")
let e = graph.add(identifier: "E")

// 2️⃣ Build the graph
b.addDependency(node: a)
c.addDependency(node: b)
d.addDependency(node: b)
e.addDependency(node: a)
b.addDependency(node: e)

// 3️⃣ Resolve execution order
if let order = try? graph.compile() {
    print("Execution order: \(order.map { $0 })")
} else {
    print("Graph contains a cycle!")
}

Testing

The repository includes a comprehensive test suite:

swift test

All tests should pass, confirming correct cycle detection and ordering logic.

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Happy graph building! 🚀