From 6770c742c7a1354517c691d0761766e94e17cbbb Mon Sep 17 00:00:00 2001
From: Joseph Humfrey <joseph.humfrey@inklestudios.com>
Date: Thu, 9 Mar 2017 16:56:09 +0000
Subject: [PATCH] Ability to pass arguments to knots (or functions) from the
 game.

---
 ink-engine-runtime/Story.cs      | 11 +++++++----
 ink-engine-runtime/StoryState.cs | 12 +++++++-----
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/ink-engine-runtime/Story.cs b/ink-engine-runtime/Story.cs
index 7a02187c..a5a96ce5 100644
--- a/ink-engine-runtime/Story.cs
+++ b/ink-engine-runtime/Story.cs
@@ -1099,14 +1099,17 @@ bool PerformLogicAndFlowControl(Runtime.Object contentObj)
         /// 
         /// </summary>
         /// <param name="path">A dot-separted path string, as specified above.</param>
-        public void ChoosePathString(string path)
+        /// <param name="arguments">Optional set of arguments to pass, if path is to a knot that takes them.</param>
+        public void ChoosePathString (string path, params object [] arguments)
         {
-            ChoosePath (new Path(path));
+            state.PassArgumentsToEvaluationStack (arguments);
+            ChoosePath (new Path (path));
         }
+
             
-        internal void ChoosePath(Path path)
+        internal void ChoosePath(Path p)
         {
-            state.SetChosenPath (path);
+            state.SetChosenPath (p);
 
             // Take a note of newly visited containers for read counts etc
             VisitChangedContainersDueToDivert ();
diff --git a/ink-engine-runtime/StoryState.cs b/ink-engine-runtime/StoryState.cs
index 640a9bae..4639a494 100755
--- a/ink-engine-runtime/StoryState.cs
+++ b/ink-engine-runtime/StoryState.cs
@@ -810,20 +810,22 @@ internal void StartExternalFunctionEvaluation (Container funcContainer, params o
             callStack = new CallStack (funcContainer);
             callStack.currentElement.type = PushPopType.Function;
 
-            // Change the callstack the variableState is looking at to be
-            // this temporary function evaluation one. We'll restore it afterwards
-            variablesState.callStack = callStack;
-
             // By setting ourselves in external function evaluation mode,
             // we're saying it's okay to end the flow without a Done or End,
             // but with a ~ return instead.
             _isExternalFunctionEvaluation = true;
 
+            PassArgumentsToEvaluationStack (arguments);
+        }
+
+        internal void PassArgumentsToEvaluationStack (params object [] arguments)
+        {
+
             // Pass arguments onto the evaluation stack
             if (arguments != null) {
                 for (int i = 0; i < arguments.Length; i++) {
                     if (!(arguments [i] is int || arguments [i] is float || arguments [i] is string)) {
-                        throw new System.ArgumentException ("ink arguments when calling EvaluateFunction must be int, float or string");
+                        throw new System.ArgumentException ("ink arguments when calling EvaluateFunction / ChoosePathStringWithParameters must be int, float or string");
                     }
 
                     PushEvaluationStack (Runtime.Value.Create (arguments [i]));