String substitution uses StringBuilder to avoid string allocations

Assets/Fungus/Flowchart/Scripts/Flowchart.cs

@@ -2,6 +2,7 @@ using UnityEngine;
 using UnityEngine.EventSystems;
 using UnityEngine.Serialization;
 using System;
+using System.Text;
 using System.Linq;
 using System.Collections;
 using System.Collections.Generic;
@@ -968,15 +969,15 @@ namespace Fungus
 		 * use the SubstituteVariables() method instead.
 		 */
 		[MoonSharp.Interpreter.MoonSharpHidden]
-		public virtual string SubstituteStrings(string input)
+		public virtual bool SubstituteStrings(StringBuilder input)
 		{
-			string subbedText = input;
-
 			// Instantiate the regular expression object.
 			Regex r = new Regex("{\\$.*?}");
 
+            bool modified = false;
+
 			// Match the regular expression pattern against a text string.
-			var results = r.Matches(input);
+            var results = r.Matches(input.ToString());
 			foreach (Match match in results)
 			{
 				string key = match.Value.Substring(2, match.Value.Length - 3);
@@ -991,12 +992,14 @@ namespace Fungus
 						variable.key == key)
 					{	
 						string value = variable.ToString();
-						subbedText = subbedText.Replace(match.Value, value);
+						input.Replace(match.Value, value);
+
+                        modified = true;
 					}
 				}
 			}
 
-			return subbedText;
+            return modified;
 		}
 
 		/**
@@ -1012,8 +1015,11 @@ namespace Fungus
 				stringSubstituer = new StringSubstituter();
 			}
 
-			string subbedText = input;
-			
+            // Use the string builder from StringSubstituter for efficiency.
+            StringBuilder sb = stringSubstituer.stringBuilder;
+            sb.Length = 0;
+            sb.Append(input);
+           			
 			// Instantiate the regular expression object.
 			Regex r = new Regex("{\\$.*?}");
 			
@@ -1033,13 +1039,20 @@ namespace Fungus
 						variable.key == key)
 					{	
 						string value = variable.ToString();
-						subbedText = subbedText.Replace(match.Value, value);
+                        sb.Replace(match.Value, value);
 					}
 				}
 			}
 
 			// Now do all other substitutions in the scene
-			return stringSubstituer.SubstituteStrings(subbedText);
+            if (stringSubstituer.SubstituteStrings(sb))
+            {
+                return sb.ToString();
+            }
+            else
+            {
+                return input;
+            }
 		}
 	}
 

Assets/Fungus/Narrative/Scripts/Localization.cs

@@ -6,6 +6,7 @@ using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
+using System.Text;
 using System.IO;
 using Ideafixxxer.CsvParser;
 
@@ -525,19 +526,19 @@ namespace Fungus
 		 * Implementation of StringSubstituter.ISubstitutionHandler.
 		 * Relaces tokens of the form {$KeyName} with the localized value corresponding to that key.
 		 */
-		public virtual string SubstituteStrings(string input)
+		public virtual bool SubstituteStrings(StringBuilder input)
 		{
 			// This method could be called from the Start method of another component, so we
 			// may need to initilize the localization system.
 			Init();
 
-			string subbedText = input;
-
 			// Instantiate the regular expression object.
 			Regex r = new Regex("{\\$.*?}");
 
+            bool modified = false;
+
 			// Match the regular expression pattern against a text string.
-			var results = r.Matches(input);
+            var results = r.Matches(input.ToString());
 			foreach (Match match in results)
 			{
 				string key = match.Value.Substring(2, match.Value.Length - 3);
@@ -546,11 +547,12 @@ namespace Fungus
 				string localizedString = Localization.GetLocalizedString(key);
 				if (localizedString != null)
 				{
-					subbedText = subbedText.Replace(match.Value, localizedString);
+					input.Replace(match.Value, localizedString);
+                    modified = true;
 				}
 			}
 
-			return subbedText;
+            return modified;
 		}
 	}
 

Assets/Fungus/Thirdparty/FungusLua/Scripts/LuaUtils.cs

@@ -3,6 +3,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System;
 using System.Linq;
+using System.Text;
 using System.Diagnostics;
 using System.Text.RegularExpressions;
 using MoonSharp.Interpreter;
@@ -319,7 +320,7 @@ namespace Fungus
         /// The string table value used depends on the currently loaded string table and active language.
         /// </summary>
 		[MoonSharpHidden]
-		public virtual string SubstituteStrings(string input)
+		public virtual bool SubstituteStrings(StringBuilder input)
         {
 			// This method could be called from the Start of another component, so
 			// we need to ensure that the LuaEnvironment has been initialized.
@@ -333,26 +334,26 @@ namespace Fungus
 			}
 					
 			if (luaEnvironment == null)
-				{
+			{
 				UnityEngine.Debug.LogError("No Lua Environment found");
-				return input;
+				return false;
 			}
 
 			if (luaEnvironment.Interpreter == null)
 			{
 				UnityEngine.Debug.LogError("No Lua interpreter found");
-				return input;
+				return false;
 			}
 				
 			MoonSharp.Interpreter.Script interpreter = luaEnvironment.Interpreter;
 
-            string subbedText = input;
-
             // Instantiate the regular expression object.
 			Regex r = new Regex("\\{\\$.*?\\}");
 
+            bool modified = false;
+
             // Match the regular expression pattern against a text string.
-			var results = r.Matches(input);
+            var results = r.Matches(input.ToString());
             foreach (Match match in results)
             {
                 string key = match.Value.Substring(2, match.Value.Length - 3);
@@ -366,7 +367,8 @@ namespace Fungus
 	                    DynValue languageEntry = stringTableVar.Table.Get(activeLanguage);
 	                    if (languageEntry.Type == DataType.String)
 	                    {
-	                        subbedText = subbedText.Replace(match.Value, languageEntry.String);
+	                        input.Replace(match.Value, languageEntry.String);
+                            modified = true;
 	                    }
 	                    continue;
 	                }
@@ -376,12 +378,13 @@ namespace Fungus
                 DynValue globalVar = interpreter.Globals.Get(key);
                 if (globalVar.Type != DataType.Nil)
                 {
-                    subbedText = subbedText.Replace(match.Value, globalVar.ToPrintString());
+                    input.Replace(match.Value, globalVar.ToPrintString());
+                    modified = true;
                     continue;
                 }
             }
 
-            return subbedText;
+            return modified;
         }
 
 		/// <summary>
@@ -390,7 +393,7 @@ namespace Fungus
 		/// </summary>
 		public virtual string Substitute(string input)
 		{
-			return stringSubstituter.SubstituteStrings(input);
+            return stringSubstituter.SubstituteStrings(input);
 		}
             
 		/// <summary>

Assets/Fungus/Thirdparty/FungusLua/Scripts/StringSubstituter.cs

@@ -17,21 +17,33 @@ namespace Fungus
 		public interface ISubstitutionHandler
 		{
 			/// <summary>
-			/// Returns a new string with tokens replaced by subsituted values.
+			/// Modifies a StringBuilder so that tokens are replaced by subsituted values.
 			/// It's up to clients how to implement substitution but the convention looks like:
 			/// "Hi {$VarName}" => "Hi John" where VarName == "John"
+            /// <returns>True if the input was modified</returns>
 			/// </summary>
-			string SubstituteStrings(string input);
+			bool SubstituteStrings(StringBuilder input);
 		}
 
 		protected List<ISubstitutionHandler> substitutionHandlers = new List<ISubstitutionHandler>();
 
+        /**
+         * The StringBuilder instance used to substitute strings optimally.
+         * This property is public to support client code optimisations.
+         */
+        public StringBuilder stringBuilder;
+
+        private int recursionDepth;
+
 		/// <summary>
 		/// Constructor which caches all components in the scene that implement ISubstitutionHandler.
+        /// <param name="recursionDepth">Number of levels of recursively embedded keys to resolve.</param>
 		/// </summary>
-		public StringSubstituter()
+        public StringSubstituter(int recursionDepth = 5)
 		{
 			CacheSubstitutionHandlers();
+            stringBuilder = new StringBuilder(1024);
+            this.recursionDepth = recursionDepth;
 		}
 
 		/// <summary>
@@ -64,28 +76,48 @@ namespace Fungus
 		/// </summary>
 		public virtual string SubstituteStrings(string input)
 		{
-            string newString = input;
+            stringBuilder.Length = 0;
+            stringBuilder.Append(input);
+
+            if (SubstituteStrings(stringBuilder))
+            {
+                return stringBuilder.ToString();
+            }
+            else
+            {
+                return input; // String wasn't modified
+            }
+		}
+
+        public virtual bool SubstituteStrings(StringBuilder input)
+        {
+            bool result = false;
 
             // Perform the substitution multiple times to expand nested keys
-            int lasthash = 0;
-            int currenthash = -1;
             int loopCount = 0; // Avoid infinite recursion loops
-
-            while (lasthash != currenthash && 
-                   loopCount < 5)
+            while (loopCount < recursionDepth)
             {
-                lasthash = newString.GetHashCode();
-    			foreach (ISubstitutionHandler handler in substitutionHandlers)
-    			{
-    				newString = handler.SubstituteStrings(newString);
-    			}
-                currenthash = newString.GetHashCode();
+                bool modified = false;
+                foreach (ISubstitutionHandler handler in substitutionHandlers)
+                {
+                    if (handler.SubstituteStrings(input))
+                    {
+                        modified = true;
+                        result = true;
+                    }
+                }
+
+                if (!modified)
+                {
+                    break;
+                }
 
                 loopCount++;
             }
 
-			return newString;
-		}
+            return result;
+        }
+
 	}
 
 }

Assets/Tests/StringSubstitution/StringSubstitutionTests.unity

@@ -1427,6 +1427,7 @@ MonoBehaviour:
   - Fungus.Command, Assembly-CSharp, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null
   - Fungus.CommandInfoAttribute, Assembly-CSharp, Version=0.0.0.0, Culture=neutral,
     PublicKeyToken=null
+  - System.Text.StringBuilder, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
   - UnityEngine.Rect, UnityEngine, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null
   boundObjects:
   - key: text
@@ -1592,7 +1593,7 @@ GameObject:
   m_Icon: {fileID: 0}
   m_NavMeshLayer: 0
   m_StaticEditorFlags: 0
-  m_IsActive: 1
+  m_IsActive: 0
 --- !u!114 &1475498171
 MonoBehaviour:
   m_ObjectHideFlags: 0

ProjectSettings/ProjectSettings.asset

@@ -117,6 +117,8 @@ PlayerSettings:
     m_Bits: 238
   iPhoneSdkVersion: 988
   iPhoneTargetOSVersion: 22
+  tvOSSdkVersion: 0
+  tvOSTargetOSVersion: 900
   uIPrerenderedIcon: 0
   uIRequiresPersistentWiFi: 0
   uIRequiresFullScreen: 1
@@ -199,6 +201,7 @@ PlayerSettings:
   wiiUSystemHeapSize: 128
   wiiUTVStartupScreen: {fileID: 0}
   wiiUGamePadStartupScreen: {fileID: 0}
+  wiiUDrcBufferDisabled: 0
   wiiUProfilerLibPath: 
   actionOnDotNetUnhandledException: 1
   enableInternalProfiler: 0
@@ -266,6 +269,7 @@ PlayerSettings:
   ps4DownloadDataSize: 0
   ps4GarlicHeapSize: 2048
   ps4Passcode: 5PN2qmWqBlQ9wQj99nsQzldVI5ZuGXbE
+  ps4UseDebugIl2cppLibs: 0
   ps4pnSessions: 1
   ps4pnPresence: 1
   ps4pnFriends: 1
@@ -331,6 +335,7 @@ PlayerSettings:
   psp2UseLibLocation: 0
   psp2InfoBarOnStartup: 0
   psp2InfoBarColor: 0
+  psp2UseDebugIl2cppLibs: 0
   psmSplashimage: {fileID: 0}
   spritePackerPolicy: 
   scriptingDefineSymbols: {}