Fix parsing of variable names quoted with backticks, and allow variable attributes to be accessed by name

Author: stackotter

Sources/MacroToolkit/Documentation.docc/Destructuring.md

@@ -48,7 +48,7 @@ attribute lists, etc.). Lets use destructuring to parse an argument list.
 ```swift
 // We're expecting exactly two arguments; a name and an age
 guard
-    let (nameExpr, ageExpr) = attribute.arguments,
+    let ((nil, nameExpr), (nil, ageExpr)) = destructure(attribute.arguments),
     let name = nameExpr.asStringLiteral?.value,
     let age = ageExpr.asIntegerLiteral?.value
 else {

Sources/MacroToolkit/Expr.swift

@@ -1,5 +1,6 @@
 import SwiftSyntax
 
+// TODO: Create wrapper for tuple syntax
 /// Wraps an expression syntax node.
 public struct Expr {
     /// The underlying syntax node.

Sources/MacroToolkit/Function.swift

@@ -45,7 +45,8 @@ public struct Function {
                 case .attribute(let attributeSyntax):
                     return .attribute(Attribute(attributeSyntax))
                 case .ifConfigDecl(let ifConfigDeclSyntax):
-                    return .conditionalCompilationBlock(ConditionalCompilationBlock(ifConfigDeclSyntax))
+                    return .conditionalCompilationBlock(
+                        ConditionalCompilationBlock(ifConfigDeclSyntax))
             }
         }
     }

Sources/MacroToolkit/MacroAttribute.swift

@@ -23,20 +23,20 @@ public struct MacroAttribute {
     /// Gets the argument with the given label.
     public func argument(labeled label: String) -> Expr? {
         (_argumentListSyntax?.first { element in
-            return element.label?.text == label
+            element.label?.text == label
         }?.expression).map(Expr.init)
     }
 
-    // TODO: Include labels alongside each argument, and add way to conditionally get arguments without labels if no labels are present.
+    // TODO: Add way to conditionally get arguments without labels if no labels are present.
     //   This is required because most of the time when matching against the list of arguments, macro authors will want to ensure there
     //   are no random extraenous labels.
     /// Gets the list of all of the attribute's arguments.
-    public var arguments: [Expr] {
+    public var arguments: [(label: String?, expr: Expr)] {
         guard let argumentList = _argumentListSyntax else {
             return []
         }
         return Array(argumentList).map { argument in
-            Expr(argument.expression)
+            (label: argument.label?.text, expr: Expr(argument.expression))
         }
     }
 

Sources/MacroToolkit/Variable.swift

@@ -44,6 +44,19 @@ public struct Variable {
         }
     }
 
+    /// Returns the attribute with the given name if the declaration has such an attribute.
+    public func attribute(named name: String) -> Attribute? {
+        for element in attributes {
+            guard case let .attribute(attribute) = element else {
+                continue
+            }
+            if attribute.name.name == name {
+                return attribute
+            }
+        }
+        return nil
+    }
+
     /// Determines whether the variable has the syntax of a stored property.
     ///
     /// This syntactic check cannot account for semantic adjustments due to,

Sources/MacroToolkit/VariableBinding.swift

@@ -1,3 +1,4 @@
+import Foundation
 import SwiftSyntax
 
 /// A variable binding (e.g. the `a: Int = 3` part of `var a: Int = 3`)
@@ -36,7 +37,8 @@ public struct VariableBinding {
     ///
     /// For example, the binding `(a, b) = (1, 2)` doesn't have an `identifier`.
     public var identifier: String? {
-        _syntax.pattern.as(IdentifierPatternSyntax.self)?.identifier.text
+        let identifier = _syntax.pattern.as(IdentifierPatternSyntax.self)?.identifier.text
+        return identifier?.trimmingCharacters(in: CharacterSet(arrayLiteral: "`"))
     }
 
     /// The type annotation supplied for the binding if any (e.g. the `Int` in `a: Int`).

Sources/MacroToolkitExamplePlugin/AddAsyncMacro.swift

@@ -76,9 +76,10 @@ public struct AddAsyncMacro: PeerMacro {
             }
             """
 
-        let continuationExpr = isResultReturn
-        ? "try await withCheckedThrowingContinuation { continuation in"
-        : "await withCheckedContinuation { continuation in"
+        let continuationExpr =
+            isResultReturn
+            ? "try await withCheckedThrowingContinuation { continuation in"
+            : "await withCheckedContinuation { continuation in"
 
         let newBody: ExprSyntax =
             """

Sources/MacroToolkitExamplePlugin/CustomCodableMacro.swift

@@ -19,7 +19,7 @@ public struct CustomCodableMacro: MemberMacro {
             if let customKeyMacro = variable.attributes.first(called: "CodableKey") {
                 guard
                     let attribute = customKeyMacro.asMacroAttribute,
-                    let customKeyValue = destructureSingle(attribute.arguments)
+                    let customKeyValue = destructureSingle(attribute.arguments.map(\.expr))
                 else {
                     return nil
                 }