1.新增context内置变量2.修复一些问题

RScriptContext.cs

@@ -169,6 +169,30 @@ namespace Convention.RScript
             }
         }
 
+        public class BuildInContext
+        {
+            private RScriptContext context;
+            public BuildInContext(RScriptContext context)
+            {
+                this.context = context;
+            }
+
+            public bool ExistVar(string name)
+            {
+                return context.Variables.ContainsKey(name);
+            }
+
+            public bool ExistNamespace(string name)
+            {
+                return context.NamespaceLabels.ContainsKey(name);
+            }
+
+            public bool ExistLabel(string name)
+            {
+                return context.Labels.ContainsKey(name);
+            }
+        }
+
         public RScriptContext(string[] expressions,
                               RScriptImportClass import = null,
                               RScriptVariables variables = null,
@@ -177,6 +201,7 @@ namespace Convention.RScript
         {
             this.Import = import ?? new();
             this.Variables = variables ?? new();
+            this.Variables.Add("context", new(typeof(object), new BuildInContext(this)));
             this.Sentences = (from item in expressions select ParseToSentence(item)).ToArray();
             if (matcher != null)
                 this.SentenceParser = matcher;
@@ -221,13 +246,26 @@ namespace Convention.RScript
             return result;
         }
 
-        public void Run(ExpressionParser parser)
+        private void BeforeRun(ExpressionParser parser)
         {
             CurrentLocalSpaceVariableNames.Clear();
             RuntimePointerStack.Clear();
             GotoPointerStack.Clear();
             CurrentLocalSpaceVariableNames.Clear();
             CurrentLocalSpaceVariableNames.Push(new());
+            foreach (var staticType in Import)
+            {
+                parser.context.Imports.AddType(staticType);
+            }
+            foreach (var (name,varObject) in Variables)
+            {
+                parser.context.Variables[name] = varObject.data;
+            }
+        }
+
+        public void Run(ExpressionParser parser)
+        {
+            BeforeRun(parser);
             for (CurrentRuntimePointer = 0; CurrentRuntimePointer < Sentences.Length; CurrentRuntimePointer++)
             {
                 RunNextStep(parser);
@@ -242,11 +280,7 @@ namespace Convention.RScript
 
         public IEnumerator RunAsync(ExpressionParser parser)
         {
-            CurrentLocalSpaceVariableNames.Clear();
-            RuntimePointerStack.Clear();
-            GotoPointerStack.Clear();
-            CurrentLocalSpaceVariableNames.Clear();
-            CurrentLocalSpaceVariableNames.Push(new());
+            BeforeRun(parser);
             for (CurrentRuntimePointer = 0; CurrentRuntimePointer < Sentences.Length; CurrentRuntimePointer++)
             {
                 var ret = RunNextStep(parser);