Adding switch statement support (#53)

Author: mobrien-ghost

Package.resolved

@@ -56,6 +56,9 @@ public final class DeclarationCollection {
     /// The collected internal(set) public variable declarations.
     public internal(set) var variables: [Variable] = []
 
+    /// The collected switch expression declarations.
+    public internal(set) var switches: [SwitchExpression] = []
+
     func reset() {
         actors = []
         classes = []
@@ -73,6 +76,7 @@ public final class DeclarationCollection {
         subscripts = []
         typealiases = []
         variables = []
+        switches = []
     }
 
     func collect(from collection: DeclarationCollection) {
@@ -92,5 +96,6 @@ public final class DeclarationCollection {
         subscripts = collection.subscripts
         typealiases = collection.typealiases
         variables = collection.variables
+        switches = collection.switches
     }
 }

Sources/SyntaxSparrow/Internal/Collectors/DeclarationCollection.swift

@@ -203,6 +203,13 @@ class RootDeclarationCollector: SyntaxVisitor {
         if let entryNode = entryNode, node.id == entryNode.id { return .visitChildren }
         let declaration = Variable(node: node)
         declarationCollection.variables.append(declaration)
-        return .visitChildren
+        return .skipChildren
+    }
+
+    override func visit(_ node: SwitchExprSyntax) -> SyntaxVisitorContinueKind {
+        if let entryNode = entryNode, node.id == entryNode.id { return .visitChildren }
+        let declaration = SwitchExpression(node: node)
+        declarationCollection.switches.append(declaration)
+        return .skipChildren
     }
 }

Sources/SyntaxSparrow/Internal/Collectors/RootDeclarationCollector.swift

@@ -0,0 +1,85 @@
+//
+//  SwitchExpressionInnerBindingMemberCollector.swift
+//  
+//
+//  Copyright (c) CheekyGhost Labs 2024. All Rights Reserved.
+//
+
+import Foundation
+import SwiftSyntax
+
+class SwitchExpressionInnerBindingMemberCollector: SkipByDefaultVisitor {
+
+    struct Binding {
+        var keyword: String = ""
+        var value: String = ""
+    }
+
+    // MARK: - Properties
+
+    private(set) var memberName: String?
+
+    private(set) var bindings: [Binding] = []
+
+    private(set) var focusedFunctionNode: FunctionCallExprSyntax?
+
+    private(set) var focusedElementListNode: LabeledExprListSyntax?
+
+    // MARK: - Helpers
+
+    func collect(_ node: SwitchCaseItemSyntax) -> SwitchExpression.SwitchCase.Item? {
+        walk(node)
+        guard let memberName else { return nil }
+        var bindingMap: [String: String] = [:]
+        bindings.forEach { bindingMap[$0.keyword] = $0.value }
+        return .innerValueBindingMember(name: memberName, elements: bindingMap)
+    }
+
+    // MARK: - Overrides
+
+    override func visit(_ node: SwitchCaseItemSyntax) -> SyntaxVisitorContinueKind {
+        return .visitChildren
+    }
+
+    override func visit(_ node: ExpressionPatternSyntax) -> SyntaxVisitorContinueKind {
+        return .visitChildren
+    }
+
+    override func visit(_ node: FunctionCallExprSyntax) -> SyntaxVisitorContinueKind {
+        guard focusedFunctionNode == nil else { return .skipChildren }
+        focusedFunctionNode = node
+        return .visitChildren
+    }
+
+    override func visit(_ node: MemberAccessExprSyntax) -> SyntaxVisitorContinueKind {
+        guard let focusedNode = focusedFunctionNode, node.parent?.id == focusedNode.id else { return .skipChildren }
+        memberName = node.declName.baseName.text.trimmed
+        return .skipChildren
+    }
+
+    override func visit(_ node: LabeledExprListSyntax) -> SyntaxVisitorContinueKind {
+        guard node.parent?.id == focusedFunctionNode?.id else { return .skipChildren }
+        guard focusedElementListNode == nil else { return .skipChildren }
+        focusedElementListNode = node
+        return .visitChildren
+    }
+
+    override func visit(_ node: LabeledExprSyntax) -> SyntaxVisitorContinueKind {
+        guard let focusedElements = focusedElementListNode, node.parent?.id == focusedElements.id else { return .skipChildren }
+        return .visitChildren
+    }
+
+    override func visit(_ node: PatternExprSyntax) -> SyntaxVisitorContinueKind {
+        guard let focusedElements = focusedElementListNode, node.parent?.parent?.id == focusedElements.id else { return .skipChildren }
+        return .visitChildren
+    }
+
+    override func visit(_ node: ValueBindingPatternSyntax) -> SyntaxVisitorContinueKind {
+        let binding = Binding(
+            keyword: node.bindingSpecifier.text.trimmed,
+            value: node.pattern.trimmedDescription
+        )
+        bindings.append(binding)
+        return .skipChildren
+    }
+}

Sources/SyntaxSparrow/Internal/Collectors/Switch/SwitchExpressionInnerBindingMemberCollector.swift

@@ -0,0 +1,39 @@
+//
+//  SwitchExpressionValueBindingCollector.swift
+//  
+//
+//  Copyright (c) CheekyGhost Labs 2024. All Rights Reserved.
+//
+
+import Foundation
+import SwiftSyntax
+
+class SwitchExpressionIsTypeCollector: SkipByDefaultVisitor {
+
+    // MARK: - Properties
+
+    private(set) var type: String?
+
+    // MARK: - Helpers
+
+    func collect(_ node: SwitchCaseItemSyntax) -> SwitchExpression.SwitchCase.Item? {
+        walk(node)
+        guard let type else { return nil }
+        return .isTypePattern(type: type)
+    }
+
+    // MARK: - Overrides
+
+    override func visit(_ node: SwitchCaseItemSyntax) -> SyntaxVisitorContinueKind {
+        return .visitChildren
+    }
+
+    override func visit(_ node: IsTypePatternSyntax) -> SyntaxVisitorContinueKind {
+        return .visitChildren
+    }
+
+    override func visit(_ node: IdentifierTypeSyntax) -> SyntaxVisitorContinueKind {
+        type = node.description
+        return .skipChildren
+    }
+}

Sources/SyntaxSparrow/Internal/Collectors/Switch/SwitchExpressionIsTypeCollector.swift

@@ -0,0 +1,44 @@
+//
+//  SwitchExpressionMemberCollector.swift
+//  
+//
+//  Copyright (c) CheekyGhost Labs 2024. All Rights Reserved.
+//
+
+import Foundation
+import SwiftSyntax
+
+class SwitchExpressionMemberCollector: SkipByDefaultVisitor {
+
+    // MARK: - Properties
+
+    private(set) var memberName: String?
+
+    private(set) var focusedExpressionNode: ExpressionPatternSyntax?
+
+    // MARK: - Helpers
+
+    func collect(_ node: SwitchCaseItemSyntax) -> SwitchExpression.SwitchCase.Item? {
+        walk(node)
+        guard let memberName else { return nil }
+        return .member(name: memberName)
+    }
+
+    // MARK: - Overrides
+
+    override func visit(_ node: SwitchCaseItemSyntax) -> SyntaxVisitorContinueKind {
+        return .visitChildren
+    }
+
+    override func visit(_ node: ExpressionPatternSyntax) -> SyntaxVisitorContinueKind {
+        guard focusedExpressionNode == nil else { return .skipChildren }
+        focusedExpressionNode = node
+        return .visitChildren
+    }
+
+    override func visit(_ node: MemberAccessExprSyntax) -> SyntaxVisitorContinueKind {
+        guard let focusedNode = focusedExpressionNode, node.parent?.id == focusedNode.id else { return .skipChildren }
+        memberName = node.declName.baseName.text.trimmed
+        return .skipChildren
+    }
+}

Sources/SyntaxSparrow/Internal/Collectors/Switch/SwitchExpressionMemberCollector.swift

@@ -0,0 +1,52 @@
+//
+//  SwitchExpressionTupleCollector.swift
+//  
+//
+//  Copyright (c) CheekyGhost Labs 2024. All Rights Reserved.
+//
+
+import Foundation
+import SwiftSyntax
+
+class SwitchExpressionTupleCollector: SkipByDefaultVisitor {
+
+    // MARK: - Properties
+
+    private(set) var memberName: String?
+
+    private(set) var elements: [String]?
+
+    private(set) var focusedExpressionNode: ExpressionPatternSyntax?
+
+    // MARK: - Helpers
+
+    func collect(_ node: SwitchCaseItemSyntax) -> SwitchExpression.SwitchCase.Item? {
+        walk(node)
+        guard let elements, memberName == nil else { return nil }
+        return .tuple(elements: elements)
+    }
+
+    // MARK: - Overrides
+
+    override func visit(_ node: SwitchCaseItemSyntax) -> SyntaxVisitorContinueKind {
+        return .visitChildren
+    }
+
+    override func visit(_ node: ExpressionPatternSyntax) -> SyntaxVisitorContinueKind {
+        guard focusedExpressionNode == nil else { return .skipChildren }
+        focusedExpressionNode = node
+        return .visitChildren
+    }
+
+    override func visit(_ node: MemberAccessExprSyntax) -> SyntaxVisitorContinueKind {
+        // This is a fallback as there should be no member syntax. If there is the result will return nil.
+        memberName = node.declName.baseName.text.trimmed
+        return .skipChildren
+    }
+
+    override func visit(_ node: TupleExprSyntax) -> SyntaxVisitorContinueKind {
+        guard let focusedExpressionNode, node.parent?.id == focusedExpressionNode.id, elements == nil else { return .skipChildren }
+        elements = node.elements.trimmedDescription.components(separatedBy: ",").map(\.trimmed)
+        return .skipChildren
+    }
+}

Sources/SyntaxSparrow/Internal/Collectors/Switch/SwitchExpressionTupleCollector.swift

@@ -0,0 +1,96 @@
+//
+//  SwitchExpressionValueBindingCollector.swift
+//  
+//
+//  Copyright (c) CheekyGhost Labs 2024. All Rights Reserved.
+//
+
+import Foundation
+import SwiftSyntax
+
+class SwitchExpressionValueBindingCollector: SkipByDefaultVisitor {
+
+    // MARK: - Properties
+
+    private(set) var memberName: String?
+
+    private(set) var keyword: String?
+
+    private(set) var sequenceElements: [String] = []
+
+    private(set) var focusedBindingNode: ValueBindingPatternSyntax?
+
+    private(set) var focusedFunctionNode: FunctionCallExprSyntax?
+
+    // MARK: - Helpers
+
+    func collect(_ node: SwitchCaseItemSyntax) -> SwitchExpression.SwitchCase.Item? {
+        walk(node)
+        guard let keyword, memberName == nil else { return nil }
+        return .valueBinding(keyWord: keyword, elements: sequenceElements)
+    }
+
+    // MARK: - Overrides
+
+    override func visit(_ node: SwitchCaseItemSyntax) -> SyntaxVisitorContinueKind {
+        return .visitChildren
+    }
+
+    override func visit(_ node: ValueBindingPatternSyntax) -> SyntaxVisitorContinueKind {
+        guard focusedBindingNode == nil else { return .skipChildren }
+        focusedBindingNode = node
+        keyword = node.bindingSpecifier.trimmedDescription
+        return .visitChildren
+    }
+
+    override func visit(_ node: ExpressionPatternSyntax) -> SyntaxVisitorContinueKind {
+        guard let focusedNode = focusedBindingNode, node.parent?.id == focusedNode.id else { return .skipChildren }
+        return .visitChildren
+    }
+
+    override func visit(_ node: MemberAccessExprSyntax) -> SyntaxVisitorContinueKind {
+        // This is a fallback as there should be no member syntax. If there is the result will return nil.
+        memberName = node.declName.baseName.text.trimmed
+        return .skipChildren
+    }
+
+    override func visit(_ node: SequenceExprSyntax) -> SyntaxVisitorContinueKind {
+        return .visitChildren
+    }
+
+    override func visit(_ node: ExprListSyntax) -> SyntaxVisitorContinueKind {
+        sequenceElements = node.map(\.trimmedDescription)
+        return .skipChildren
+    }
+
+    /*
+     Initially listened for the variants I could derive from token exploration. However, as it always
+     ends up adding the `node.trimmedDescription`, and there is always an `ExprListSyntax` element that
+     contains them, the `ExprListSyntax` visitor override will just map the trimmed description value
+     into the sequence. Leaving these in as reference for future refactor/clean-up.
+     */
+
+//    override func visit(_ node: UnresolvedPatternExprSyntax) -> SyntaxVisitorContinueKind {
+//        return .visitChildren
+//    }
+//
+//    override func visit(_ node: TypeExprSyntax) -> SyntaxVisitorContinueKind {
+//        sequenceElements.append(node.trimmedDescription)
+//        return .skipChildren
+//    }
+//
+//    override func visit(_ node: UnresolvedAsExprSyntax) -> SyntaxVisitorContinueKind {
+//        sequenceElements.append(node.trimmedDescription)
+//        return .skipChildren
+//    }
+//
+//    override func visit(_ node: UnresolvedIsExprSyntax) -> SyntaxVisitorContinueKind {
+//        sequenceElements.append(node.trimmedDescription)
+//        return .skipChildren
+//    }
+//
+//    override func visit(_ node: IdentifierPatternSyntax) -> SyntaxVisitorContinueKind {
+//        sequenceElements.append(node.identifier.trimmedDescription)
+//        return .skipChildren
+//    }
+}