new statement EVAL

Author: aafent

FAST.FBasic.InteractiveConsole/FBasicIC_Setup.cs

@@ -90,6 +90,8 @@ private void setupEnvironment()
             env.AddLibrary(new FBasicJsonLibrary());
             env.AddLibrary(new FBasicTemplatingLibrary());
             env.AddLibrary(new FBasicAIChat());
+            env.AddLibrary(new FBasicLanguageExtensions());
+
             env.AddVariable("table.column", "myColumn1");
 
             FBasicEvents.Reset();

FAST.FBasic.InteractiveConsole/Tests/eval.bas

@@ -0,0 +1,16 @@
+REM Test program for EVAL statements
+REM Category: Flow Control
+REM
+RESULT 5
+
+let code="
+print RESULTVALUE
+let X=10
+print X
+"
+
+eval code
+let X=X+1
+print "X="+X
+
+

FAST.FBasic.LibraryToolkit/Core/InterpreterHelper.cs

@@ -35,6 +35,7 @@ public static bool IsStatement(Token token)
                 case Token.Dump:
                 case Token.Call:
                 case Token.Chain:
+                case Token.Eval:
                 case Token.ForEach:
                 case Token.EndForEach:
                 case Token.SData:

FAST.FBasic.LibraryToolkit/Core/Token.cs

@@ -30,6 +30,7 @@ public enum Token
         Dump,
         Call,
         Chain,
+        Eval,
         ForEach,
         EndForEach,
         SData,

FAST.FBasicInterpreter/Core/Interpreter_Elements.cs

@@ -31,6 +31,7 @@ void Statement()
                 case Token.Dump: DumpStatement(); break;
                 case Token.Call: CallStatement(); break;
                 case Token.Chain: ChainStatement(); break;
+                case Token.Eval: EvalStatement(); break;
                 case Token.ForEach: ForEachStatement(); break;
                 case Token.EndForEach: EndForEachStatement(); break;
                 case Token.SData: SDataStatement(); break;    

FAST.FBasicInterpreter/Core/Interpreter_Statements.cs

@@ -138,6 +138,34 @@ void ChainStatement()
             return;
         }
 
+        /// <summary>
+        /// EVAL
+        /// </summary>
+        void EvalStatement()
+        {
+            // (v) load the chain source program
+            string srcCode = Expr().ToString();
+
+            // (v) save the current program state
+            var oldState = this.GetState();
+
+            //// (v) Set the new chain program and execute it
+            lex.SetSource(srcCode);
+            exit = false;
+            GetNextToken();
+            while (!exit) Line(); // do all lines
+            exit = false;
+
+            // (v) restore the old program state
+            this.SetState(oldState);
+
+            // (v) continue with the next instruction
+
+            return;
+        }
+
+
+
         /// <summary>
         /// HALT | END
         /// </summary>

FAST.FBasicInterpreter/Core/Lexer.cs

@@ -168,6 +168,7 @@ public Token GetToken()
                     case "RETURN": return Token.Return;
                     case "CALL": return Token.Call;
                     case "CHAIN": return Token.Chain;
+                    case "EVAL": return Token.Eval;
                     case "FOREACH": return Token.ForEach;
                     case "ENDFOREACH": return Token.EndForEach;
 

FAST.FBasicInterpreter/Libraries/FBasicLanguageExtensions.cs

@@ -0,0 +1,64 @@
+//
+// Language Extensions Statements: 
+//
+// 
+
+using System.Text;
+
+namespace FAST.FBasicInterpreter
+{
+    public class FBasicLanguageExtensions : IFBasicLibraryWithMemory, IDisposable
+    {
+        private IInterpreter inter;
+
+        public string uniqueName => "FBasicLanguageExtensions";
+
+        public FBasicLanguageExtensions()
+        {
+            //IFBasicFileManagementLayer fileManager=new zzzzzzz();
+            //this.fileManager=fileManager;
+        }
+
+        public void InstallAll(IInterpreter interpreter)
+        {
+            this.inter = interpreter;
+
+            interpreter.AddStatement("EVAL", EVAL);
+
+        }
+
+        private static void EVAL(IInterpreter interpreter)
+        {
+            // Syntax: EVAL value|variable
+            //  
+            string code = interpreter.ValueOrVariable(true).String;
+            interpreter.GetNextToken();
+
+
+        }
+         
+        public void ClearMemory()
+        {
+            var variables = inter.GetVariables();
+            foreach (var variable in variables)
+            {
+                if (variable.Value.Type != ValueType.Object) continue;
+
+                if (variable.Value.Object is Stream)
+                {
+                    var stream = ((Stream)variable.Value.Object);
+                    stream.Flush();
+                    stream.Close();
+                    stream.Dispose();
+                    stream = null;
+                }
+            }
+        }
+
+        public void Dispose()
+        {
+            ClearMemory();
+        }
+    }
+
+}