Create experimental interactive terminal backend (using TermKit)

Author: stackotter

.github/workflows/swift-linux.yml

@@ -16,6 +16,17 @@ jobs:
         sudo apt update && \
         sudo apt install -y libgtk-4-dev clang
     - name: Build
-      run: swift build -v
+      run: |
+        swift build SwiftCrossUI && \
+        swift build GtkBackend && \
+        swift build CounterExample && \
+        swift build RandomNumberGeneratorExample && \
+        swift build WindowPropertiesExample && \
+        swift build GreetingGeneratorExample && \
+        swift build FileViewerExample && \
+        swift build NavigationExample && \
+        swift build SplitExample && \
+        swift build GtkCodeGen && \
+        swift build GtkExample
     - name: Test
       run: swift test

.github/workflows/swift-macos.yml

@@ -17,6 +17,17 @@ jobs:
     - name: Patch libffi
       run: sed -i '' 's/-I..includedir.//g' /usr/local/Homebrew/Library/Homebrew/os/mac/pkgconfig/13/libffi.pc
     - name: Build
-      run: swift build -v
+      run: |
+        swift build SwiftCrossUI && \
+        swift build GtkBackend && \
+        swift build CounterExample && \
+        swift build RandomNumberGeneratorExample && \
+        swift build WindowPropertiesExample && \
+        swift build GreetingGeneratorExample && \
+        swift build FileViewerExample && \
+        swift build NavigationExample && \
+        swift build SplitExample && \
+        swift build GtkCodeGen && \
+        swift build GtkExample
     - name: Test
       run: swift test

Package.resolved

@@ -141,6 +141,22 @@ if checkSDL2Installed() {
     )
 }
 
+// TODO: Conditionally include TermKit backend
+conditionalTargets.append(
+    .target(
+        name: "CursesBackend",
+        dependencies: ["SwiftCrossUI", "TermKit"]
+    )
+)
+backendTargets.append("CursesBackend")
+exampleDependencies.append("CursesBackend")
+dependencies.append(
+    .package(
+        url: "https://github.com/migueldeicaza/TermKit",
+        revision: "3bce85d1bafbbb0336b3b7b7e905c35754cb9adf"
+    )
+)
+
 let package = Package(
     name: "swift-cross-ui",
     platforms: [.macOS(.v10_15)],

Package.swift

@@ -0,0 +1,120 @@
+import Foundation
+import SwiftCrossUI
+import TermKit
+
+public struct CursesBackend: AppBackend {
+    public typealias Widget = TermKit.View
+
+    public init(appIdentifier: String) {}
+
+    public func run<AppRoot: App>(
+        _ app: AppRoot,
+        _ setViewGraph: @escaping (ViewGraph<AppRoot>) -> Void
+    ) where AppRoot.Backend == Self {
+        let viewGraph = ViewGraph(for: app, backend: self)
+        setViewGraph(viewGraph)
+
+        Application.prepare()
+        let root = RootView()
+        root.addSubview(viewGraph.rootNode.widget)
+        Application.top.addSubview(root)
+        Application.run()
+    }
+
+    public func runInMainThread(action: @escaping () -> Void) {
+        DispatchQueue.main.async {
+            action()
+        }
+    }
+
+    public func show(_ widget: Widget) {
+        widget.setNeedsDisplay()
+    }
+
+    public func createVStack(spacing: Int) -> Widget {
+        return View()
+    }
+
+    public func addChild(_ child: Widget, toVStack container: Widget) {
+        // TODO: Properly calculate layout
+        child.y = Pos.at(container.subviews.count)
+        container.addSubview(child)
+    }
+
+    public func setSpacing(ofVStack container: Widget, to spacing: Int) {}
+
+    public func createHStack(spacing: Int) -> Widget {
+        return View()
+    }
+
+    public func addChild(_ child: Widget, toHStack container: Widget) {
+        // TODO: Properly calculate layout
+        child.y = Pos.at(container.subviews.count)
+        container.addSubview(child)
+    }
+
+    public func setSpacing(ofHStack container: Widget, to spacing: Int) {}
+
+    public func createTextView(content: String, shouldWrap: Bool) -> Widget {
+        let label = Label(content)
+        label.width = Dim.fill()
+        return label
+    }
+
+    public func setContent(ofTextView textView: Widget, to content: String) {
+        let label = textView as! Label
+        label.text = content
+    }
+
+    public func setWrap(ofTextView textView: Widget, to shouldWrap: Bool) {}
+
+    public func createButton(label: String, action: @escaping () -> Void) -> Widget {
+        let button = TermKit.Button(label, clicked: action)
+        button.height = Dim.sized(1)
+        return button
+    }
+
+    public func setLabel(ofButton button: Widget, to label: String) {
+        (button as! TermKit.Button).text = label
+    }
+
+    public func setAction(ofButton button: Widget, to action: @escaping () -> Void) {
+        (button as! TermKit.Button).clicked = { _ in
+            action()
+        }
+    }
+
+    // TODO: Properly implement padding container. Perhaps use a conversion factor to
+    //   convert the pixel values to 'characters' of padding
+    public func createPaddingContainer(for child: Widget) -> Widget {
+        return child
+    }
+
+    public func getChild(ofPaddingContainer container: Widget) -> Widget {
+        return container
+    }
+
+    public func setPadding(
+        ofPaddingContainer container: Widget,
+        top: Int,
+        bottom: Int,
+        leading: Int,
+        trailing: Int
+    ) {}
+}
+
+class RootView: TermKit.View {
+    override func processKey(event: KeyEvent) -> Bool {
+        if super.processKey(event: event) {
+            return true
+        }
+
+        switch event.key {
+            case .controlC, .esc:
+                Application.requestStop()
+                return true
+            default:
+                return false
+        }
+    }
+}