Fix exception when accessing the current frame in a stateless slide

Author: bnorm

storyboard-core/src/commonMain/kotlin/dev/bnorm/storyboard/core/Storyboard.kt

@@ -61,8 +61,17 @@ class Storyboard private constructor(
     var direction by mutableStateOf(AdvanceDirection.Forward)
         private set
 
-    val currentFrame: Frame
-        get() = node.currentState.let { it.frames[it.stateIndex.currentState] }
+     val currentFrame: Frame by derivedStateOf {
+        val currentNode = node.currentState
+        if (currentNode.frames.isEmpty()) {
+            when (direction) {
+                AdvanceDirection.Forward -> currentNode.previousFrame()!!
+                AdvanceDirection.Backward -> currentNode.nextFrame()!!
+            }
+        } else {
+            currentNode.frames[currentNode.stateIndex.currentState]
+        }
+    }
 
     val advancementProgress: Float
         get() = node.fraction.takeIf { it != 0.0f }

storyboard-core/src/commonMain/kotlin/dev/bnorm/storyboard/core/internal/SlideNode.kt

@@ -142,6 +142,28 @@ internal class SlideNode<T> private constructor(
         }
     }
 
+    fun nextFrame(): Storyboard.Frame? {
+        var iter = next
+        while (iter != null) {
+            if (iter.frames.isNotEmpty()) {
+                return iter.frames.first()
+            }
+            iter = iter.next
+        }
+        return null
+    }
+
+    fun previousFrame(): Storyboard.Frame? {
+        var iter = prev
+        while (iter != null) {
+            if (iter.frames.isNotEmpty()) {
+                return iter.frames.last()
+            }
+            iter = iter.prev
+        }
+        return null
+    }
+
     override fun compareTo(other: SlideNode<*>): Int {
         return compareValues(slideIndex, other.slideIndex)
     }

storyboard-easel/src/commonMain/kotlin/dev/bnorm/storyboard/easel/StoryboardOverview.kt

@@ -123,7 +123,7 @@ fun StoryboardOverview(
 
 class StoryboardOverview private constructor(
     val storyboard: Storyboard,
-    val columns: ImmutableList<Column>,
+    internal val columns: ImmutableList<Column>,
 ) {
     private var _isVisible = mutableStateOf(false)
     var isVisible: Boolean
@@ -135,7 +135,7 @@ class StoryboardOverview private constructor(
         }
 
     var currentColumnIndex by mutableStateOf(0)
-    val currentItem: Item
+    internal val currentItem: Item
         get() = columns[currentColumnIndex].let { it.items[it.currentItemIndex] }
 
     fun jumpTo(columnIndex: Int, itemIndex: Int) {
@@ -164,7 +164,7 @@ class StoryboardOverview private constructor(
     }
 
     @Immutable
-    class Column(
+    internal class Column(
         val slide: Slide<*>,
         val index: Int,
         val items: ImmutableList<Item>,
@@ -173,7 +173,7 @@ class StoryboardOverview private constructor(
     }
 
     @Immutable
-    class Item(
+    internal class Item(
         val frame: Storyboard.Frame,
     )
 
@@ -182,10 +182,8 @@ class StoryboardOverview private constructor(
             val columns = storyboard.slides
                 .mapIndexed { slideIndex, slide ->
                     val items = slide.states
-                        .mapIndexedNotNull { stateIndex, _ ->
-                            Item(
-                                frame = Storyboard.Frame(slideIndex, stateIndex)
-                            )
+                        .mapIndexed { stateIndex, _ ->
+                            Item(frame = Storyboard.Frame(slideIndex, stateIndex))
                         }
                         .toImmutableList()
 

storyboard-text/src/commonMain/kotlin/dev/bnorm/storyboard/text/highlight/Kotlin.kt

@@ -26,6 +26,7 @@ internal fun highlightKotlin(
 
             fun AnnotatedString.Builder.addStyle(token: Token): Token {
                 when (token.type) {
+                    KotlinLexer.Tokens.AS_SAFE,
                     KotlinLexer.Tokens.GET,
                     KotlinLexer.Tokens.SET,
                     KotlinLexer.Tokens.FUN,
@@ -34,6 +35,8 @@ internal fun highlightKotlin(
                     KotlinLexer.Tokens.CLASS,
                     KotlinLexer.Tokens.INTERFACE,
                     KotlinLexer.Tokens.TYPE_ALIAS,
+                    KotlinLexer.Tokens.CONSTRUCTOR,
+                    KotlinLexer.Tokens.BY,
                     KotlinLexer.Tokens.VAL,
                     KotlinLexer.Tokens.VAR,
                     KotlinLexer.Tokens.COMPANION,
@@ -49,8 +52,11 @@ internal fun highlightKotlin(
                     KotlinLexer.Tokens.WHILE,
                     KotlinLexer.Tokens.THROW,
                     KotlinLexer.Tokens.RETURN,
+                    KotlinLexer.Tokens.AS,
                     KotlinLexer.Tokens.IS,
                     KotlinLexer.Tokens.IN,
+                    KotlinLexer.Tokens.NOT_IS,
+                    KotlinLexer.Tokens.NOT_IN,
                     KotlinLexer.Tokens.PUBLIC,
                     KotlinLexer.Tokens.PRIVATE,
                     KotlinLexer.Tokens.PROTECTED,
@@ -68,12 +74,14 @@ internal fun highlightKotlin(
                     KotlinLexer.Tokens.BooleanLiteral,
                         -> addStyle(codeStyle.keyword, token)
 
+                    KotlinLexer.Tokens.RealLiteral,
+                    KotlinLexer.Tokens.FloatLiteral,
+                    KotlinLexer.Tokens.DoubleLiteral,
                     KotlinLexer.Tokens.IntegerLiteral,
                     KotlinLexer.Tokens.HexLiteral,
                     KotlinLexer.Tokens.BinLiteral,
-                    KotlinLexer.Tokens.RealLiteral,
-                    KotlinLexer.Tokens.LongLiteral,
                     KotlinLexer.Tokens.UnsignedLiteral,
+                    KotlinLexer.Tokens.LongLiteral,
                         -> addStyle(codeStyle.number, token)
 
                     KotlinLexer.Tokens.CharacterLiteral,