diff --git a/Parser/ExpressionParser.cs b/Parser/ExpressionParser.cs
index 937bc95..36f6751 100644
--- a/Parser/ExpressionParser.cs
+++ b/Parser/ExpressionParser.cs
@@ -1,12 +1,62 @@
 using Flee.PublicTypes;
-using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
-namespace Convention.RScript.Parser
+namespace Convention.RScript
 {
+    public static class ExpressionMath
+    {
+        public static int Sign(double value, double accuracy = ExpressionExtension.DefaultDoubleAccuracy)
+        {
+            if (value.IsCloseToZero(accuracy))
+                return 0;
+            return value > 0 ? 1 : -1;
+        }
+
+        public static int Compare(double value1, double value2, double accuracy = ExpressionExtension.DefaultDoubleAccuracy)
+        {
+            if (value1.IsClose(value2, accuracy))
+                return 0;
+            return value1 > value2 ? 1 : -1;
+        }
+
+        public static bool IsBetween(double value, double minValue, double maxValue, double accuracy = ExpressionExtension.DefaultDoubleAccuracy)
+        {
+            return Compare(value, minValue, accuracy) >= 0 && Compare(value, maxValue, accuracy) <= 0;
+        }
+
+        public static bool IsBetweenExclusive(double value, double minValue, double maxValue, double accuracy = ExpressionExtension.DefaultDoubleAccuracy)
+        {
+            return Compare(value, minValue, accuracy) > 0 && Compare(value, maxValue, accuracy) < 0;
+        }
+
+        public static int ToInt(double value)
+        {
+            return (int)value;
+        }
+
+        public static int ToInt(float value)
+        {
+            return (int)value;
+        }
+        public static int ToInt(int value)
+        {
+            return (int)value;
+        }
+
+        public static double ToDouble(float value)
+        {
+            return (double)value;
+        }
+
+        public static double ToDouble(int value)
+        {
+            return (double)value;
+        }
+        public static double ToDouble(double value)
+        {
+            return (double)value;
+        }
+    }
     public static class ExpressionExtension
     {
         public const double DefaultDoubleAccuracy = 1e-7;
@@ -32,7 +82,10 @@ namespace Convention.RScript.Parser
             return !(double.IsInfinity(value) || double.IsNaN(value) || value > maximumAbsoluteError || value < -maximumAbsoluteError);
         }
     }
+}
 
+namespace Convention.RScript.Parser
+{
     public class ExpressionParser
     {
         public readonly ExpressionContext context;
diff --git a/PublicTypes/RScriptVariables.cs b/PublicTypes/RScriptVariables.cs
index 2502924..bd4a110 100644
--- a/PublicTypes/RScriptVariables.cs
+++ b/PublicTypes/RScriptVariables.cs
@@ -11,7 +11,34 @@ namespace Convention.RScript
     public struct RScriptVariableEntry
     {
         public Type type;
-        public object data;
+        public object data
+        {
+            readonly get
+            {
+                return internalData;
+            }
+            set
+            {
+                if (type == null)
+                {
+                    type = value.GetType();
+                    internalData = value;
+                    return;
+                }
+                internalData = Convert.ChangeType(value, type);
+            }
+        }
+        private object internalData;
+
+        public RScriptVariableEntry(object data) : this()
+        {
+            this.data = data;
+        }
+        public RScriptVariableEntry(Type type, object data) : this()
+        {
+            this.type = type;
+            this.data = data;
+        }
     }
     public class RScriptVariables : IDictionary<string, RScriptVariableEntry>
     {
diff --git a/RScriptContext.cs b/RScriptContext.cs
index 40275b2..c312358 100644
--- a/RScriptContext.cs
+++ b/RScriptContext.cs
@@ -206,7 +206,7 @@ namespace Convention.RScript
             }
             if (CurrentLocalSpaceVariableNames.Peek().Contains(varName) == false)
             {
-                Variables.Add(varName, new() { type = varType, data = varDefaultValue });
+                Variables.Add(varName, new(varType, varDefaultValue));
                 parser.context.Variables[varName] = varDefaultValue;
                 CurrentLocalSpaceVariableNames.Peek().Add(varName);
             }
@@ -350,48 +350,59 @@ namespace Convention.RScript
         private object RunNextStep(ExpressionParser parser)
         {
             var sentence = CurrentSentence;
-            switch (sentence.mode)
+            try
             {
-                case RScriptSentence.Mode.Expression:
-                    return parser.Evaluate(sentence.content);
-                case RScriptSentence.Mode.DefineVariable:
-                    {
-                        DoDefineVariable(parser, sentence);
-                    }
-                    break;
-                case RScriptSentence.Mode.EnterNamespace:
-                    {
-                        DoEnterNamespace(parser);
-                    }
-                    break;
-                case RScriptSentence.Mode.ExitNamespace:
-                    {
-                        DoExitNamespace(parser);
-                    }
-                    break;
-                case RScriptSentence.Mode.Goto:
-                    {
-                        DoGoto(parser, sentence);
-                    }
-                    break;
-                case RScriptSentence.Mode.Breakpoint:
-                    {
-                        DoBreakpoint(parser, sentence);
-                    }
-                    break;
-                case RScriptSentence.Mode.Backpoint:
-                    {
-                        DoBackpoint(parser, sentence);
-                    }
-                    break;
-                case RScriptSentence.Mode.NamedSpace:
-                    {
-                        DoEnterNamedSpace(sentence);
-                    }
-                    break;
-                default:
-                    // Do nothing
-                    break;
+                switch (sentence.mode)
+                {
+                    case RScriptSentence.Mode.Expression:
+                        return parser.Evaluate(sentence.content);
+                    case RScriptSentence.Mode.DefineVariable:
+                        {
+                            DoDefineVariable(parser, sentence);
+                        }
+                        break;
+                    case RScriptSentence.Mode.EnterNamespace:
+                        {
+                            DoEnterNamespace(parser);
+                        }
+                        break;
+                    case RScriptSentence.Mode.ExitNamespace:
+                        {
+                            DoExitNamespace(parser);
+                        }
+                        break;
+                    case RScriptSentence.Mode.Goto:
+                        {
+                            DoGoto(parser, sentence);
+                        }
+                        break;
+                    case RScriptSentence.Mode.Breakpoint:
+                        {
+                            DoBreakpoint(parser, sentence);
+                        }
+                        break;
+                    case RScriptSentence.Mode.Backpoint:
+                        {
+                            DoBackpoint(parser, sentence);
+                        }
+                        break;
+                    case RScriptSentence.Mode.NamedSpace:
+                        {
+                            DoEnterNamedSpace(sentence);
+                        }
+                        break;
+                    default:
+                        // Do nothing
+                        break;
+                }
+            }
+            catch (RScriptRuntimeException)
+            {
+                throw;
+            }
+            catch (Exception ex)
+            {
+                throw new RScriptRuntimeException($"Runtime error: {ex.Message}", CurrentRuntimePointer, ex);
             }
             return null;
         }