SwiftCompilerPlugin

Swift macros without requiring swift-syntax

This project extracts the bare minimum from swift-syntax to be able to build a macro in Xcode 15. All you get are the strings, no fancy object trees.

If nothing else it will allow you to see what is really sent to your plugin before it's converted to structures etc.

Example

Here's the classic example from the default Xcode template which implements stringify renamed here to be ExpressionMacro.

@freestanding(expression)
public macro ExpressionMacro<T>(_ value: T) -> (T, String) = #externalMacro(module: "ExampleMacros", type: "ExpressionMacro")

...

let (result, code) = #ExpressionMacro(a + b)
(a + b, "a + b")
/* {
  "expandFreestandingMacro" : {
    "macro" : {
      "moduleName" : "ExampleMacros",
      "name" : "ExpressionMacro",
      "typeName" : "ExpressionMacro"
    },
    "syntax" : {
      "kind" : "expression",
      "location" : {
        "fileID" : "ExampleClient\/main.swift",
        "fileName" : "•••/SwiftCompilerPlugin\/Examples\/Sources\/ExampleClient\/main.swift",
        "line" : 7,
        "offset" : 78,
        "column" : 22
      },
      "source" : "#ExpressionMacro(a + b)"
    },
    "discriminator" : "$s13ExampleClient33_C7C48FD1C44CD1E5F2188E7B86F2D462Ll15ExpressionMacrofMf_",
    "macroRole" : "expression"
  }
}*/