feat: Adds result view to better handle errors, integrates it into project view.

Sources/Styleguide/ResultView.swift

@@ -0,0 +1,78 @@
+import Elementary
+import Foundation
+
+public struct ResultView<
+  V: Sendable,
+  E: Error,
+  ValueView: HTML,
+  ErrorView: HTML
+>: HTML {
+
+  let onSuccess: @Sendable (V) -> ValueView
+  let onError: @Sendable (E) -> ErrorView
+  let result: Result<V, E>
+
+  public init(
+    result: Result<V, E>,
+    @HTMLBuilder onSuccess: @escaping @Sendable (V) -> ValueView,
+    @HTMLBuilder onError: @escaping @Sendable (E) -> ErrorView
+  ) {
+    self.result = result
+    self.onError = onError
+    self.onSuccess = onSuccess
+  }
+
+  public var body: some HTML {
+    switch result {
+    case .success(let value):
+      onSuccess(value)
+    case .failure(let error):
+      onError(error)
+    }
+  }
+}
+
+extension ResultView {
+
+  public init(
+    result: Result<V, E>,
+    @HTMLBuilder onSuccess: @escaping @Sendable (V) -> ValueView
+  ) where ErrorView == Styleguide.ErrorView<E> {
+    self.init(result: result, onSuccess: onSuccess) { error in
+      Styleguide.ErrorView(error: error)
+    }
+  }
+
+  public init(
+    catching: @escaping @Sendable () async throws(E) -> V,
+    @HTMLBuilder onSuccess: @escaping @Sendable (V) -> ValueView
+  ) async where ErrorView == Styleguide.ErrorView<E> {
+    await self.init(
+      result: .init(catching: catching),
+      onSuccess: onSuccess
+    ) { error in
+      Styleguide.ErrorView(error: error)
+    }
+  }
+}
+
+extension ResultView: Sendable where Error: Sendable, ValueView: Sendable, ErrorView: Sendable {}
+
+public struct ErrorView<E: Error>: HTML, Sendable where Error: Sendable {
+
+  let error: E
+
+  public init(error: E) {
+    self.error = error
+  }
+
+  public var body: some HTML<HTMLTag.div> {
+    div {
+      h1(.class("text-2xl font-bold text-error")) { "Oops: Error" }
+      p {
+        "\(error)"
+      }
+    }
+  }
+
+}