is a generic patching engine and DSL for Swift, based on JSON Patch's operations (Add, Remove, Replace, Copy, Move, and Test).

It is used by Patchouli JSON, an ergonomic implemention of JSON Patch for Swift.

It has two major parts: a DSL that feels similar to SwiftUI, for constructing the patch, and a tree reducer which then performs the patching using appropriate functions.

The representation of patchable data and the DSL are both generic, which means that you can write a patcher for anything you like.

Patchouli Core contains a toy string patcher for demonstration purposes:

// Input: "Hello World"
// Patched result: "Goodbye my friend"

let stringPatchContent: StringPatchContent = Content("Hello World") {
    Replace(address: "Hello", with: "Goodbye")
    Replace(address: "World", with: "my friend")
}

let result: String = try stringPatchContent.reduced()

It has two major parts: a DSL that feels similar to SwiftUI, for constructing the patch, and a tree reducer which then performs the patching using appropriate functions.

The representation of patchable data and the DSL are both generic, which means that you can write a patcher for anything you like.