Begin work on outlining dynamic side

PkmnLib.Dynamic/ScriptHandling/ScriptIterator.cs

@@ -0,0 +1,71 @@
+using System.Collections;
+
+namespace PkmnLib.Dynamic.ScriptHandling;
+
+public class ScriptIterator : IEnumerable<ScriptContainer>
+{
+    private readonly IReadOnlyList<IEnumerable<ScriptContainer>> _scripts;
+    private int _index = -1;
+    private int _setIndex = -1;
+
+    public ScriptIterator(IReadOnlyList<IEnumerable<ScriptContainer>> scripts)
+    {
+        _scripts = scripts;
+    }
+
+    bool IncrementToNext()
+    {
+        if (_index != -1)
+        {
+            var current = _scripts[_index];
+            if (current is IScriptSet)
+            {
+                _setIndex += 1;
+                if (_setIndex >= current.Count())
+                {
+                    _setIndex = -1;
+                }
+                else
+                {
+                    return true;
+                }
+            }
+        }
+
+        _index += 1;
+        for (; _index < _scripts.Count; _index++)
+        {
+            switch (_scripts[_index])
+            {
+                case IScriptSet:
+                    _setIndex = 0;
+                    return true;
+                case ScriptContainer { IsEmpty: false }:
+                    return true;
+            }
+        }
+
+        return false;
+    }
+    
+    /// <inheritdoc />
+    public IEnumerator<ScriptContainer> GetEnumerator()
+    {
+        while (IncrementToNext())
+        {
+            var current = _scripts[_index];
+            yield return current switch
+            {
+                IScriptSet set => set.At(_setIndex),
+                ScriptContainer container => container,
+                _ => throw new InvalidOperationException("Invalid script type")
+            };
+        }
+    }
+
+    /// <inheritdoc />
+    IEnumerator IEnumerable.GetEnumerator()
+    {
+        return GetEnumerator();
+    }
+}