added basic try/catch/finally/throw exception handling support

bizzehdee · Sep 26, 2020 · e8b239f · e8b239f
1 parent 4d43704
commit e8b239f
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Showing 10 changed files with 225 additions and 7 deletions.
diff --git a/DScript.Demo/testscript.js b/DScript.Demo/testscript.js
@@ -18,4 +18,25 @@ var myRegex = /see (chapter \d+(\.\d)*)/i;
 var matches = testString.match(myRegex);
 console.log(matches[1]);
 
-console.log(p);
+console.log(p);
+
+try {
+
+    var x = 1;
+    throw "this broke";
+}
+catch (ex) {
+    var pns = "Exception message: " + ex;
+    console.log(pns);
+}
+
+try {
+
+    var x = 1;
+}
+catch (ex) {
+
+}
+finally {
+
+}
diff --git a/DScript.Test/DScript.Test.csproj b/DScript.Test/DScript.Test.csproj
@@ -12,8 +12,8 @@
 
   <ItemGroup>
     <PackageReference Include="nunit" Version="3.12.0" />
-    <PackageReference Include="NUnit3TestAdapter" Version="3.15.1" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="3.17.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.7.1" />
   </ItemGroup>
 
   <ItemGroup>
@@ -139,6 +139,12 @@
     <None Update="Tests\test036.js">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
     </None>
+    <None Update="Tests\test037.js">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+    <None Update="Tests\test038.js">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
   </ItemGroup>
 
 </Project>
diff --git a/DScript.Test/ScriptVarTests.cs b/DScript.Test/ScriptVarTests.cs
@@ -0,0 +1,27 @@
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace DScript.Test
+{
+    public class ScriptVarTests
+    {
+        [Test]
+        public void EmptyScriptVarIsUndefined()
+        {
+            var v = new ScriptVar();
+
+            Assert.IsTrue(v.IsUndefined);
+        }
+
+        [Test]
+        public void BoolScriptVarIsIntAndTrue()
+        {
+            var v = new ScriptVar(true);
+
+            Assert.IsTrue(v.IsInt);
+            Assert.IsTrue(v.Bool);
+        }
+    }
+}
diff --git a/DScript.Test/Tests/test037.js b/DScript.Test/Tests/test037.js
@@ -0,0 +1,14 @@
+function throwsException() {
+    throw "Some Exception Happened";
+}
+
+try {
+    throwsException();
+} catch (e) {
+
+    result = 0;
+}
+finally {
+
+    result = 1;
+}
diff --git a/DScript.Test/Tests/test038.js b/DScript.Test/Tests/test038.js
@@ -0,0 +1,11 @@
+function throwsException() {
+    throw "Some Exception Happened";
+}
+
+try {
+    throwsException();
+} catch (e) {
+
+}
+
+result = 1;
diff --git a/DScript/JITException.cs b/DScript/JITException.cs
@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace DScript
+{
+    class JITException : Exception
+    {
+        public JITException()
+        {
+
+        }
+
+        public JITException(string message) : 
+            base(message)
+        {
+
+        }
+    }
+}
diff --git a/DScript/ScriptEngine.Statement.cs b/DScript/ScriptEngine.Statement.cs
@@ -294,6 +294,104 @@ private void Statement(ref bool execute)
                     }
                 }
             }
+            else if(currentLexer.TokenType == ScriptLex.LexTypes.RTry)
+            {
+                var tryBlock = ParseDefinition(ScriptLex.LexTypes.RTry);
+                ScriptVarLink catchBlock = null, finallyBlock = null;
+
+                var originalLexer = currentLexer;
+
+                if (currentLexer.TokenType == ScriptLex.LexTypes.RCatch)
+                {
+                    catchBlock = ParseDefinition(ScriptLex.LexTypes.RCatch);
+                }
+
+                if (currentLexer.TokenType == ScriptLex.LexTypes.RFinally)
+                {
+                    finallyBlock = ParseDefinition(ScriptLex.LexTypes.RFinally);
+                }
+
+                try
+                {
+                    var oldLex = currentLexer;
+                    var newLex = new ScriptLex(tryBlock.Var.String);
+                    currentLexer = newLex;
+
+                    Block(ref execute);
+
+                    execute = true;
+
+                    currentLexer = oldLex;
+                }
+                catch(JITException ex)
+                {
+                    if (catchBlock != null)
+                    {
+                        var catchScope = new ScriptVar(null, ScriptVar.Flags.Object);
+
+                        var v = catchBlock?.Var?.FirstChild;
+                        if(v != null)
+                        {
+                            catchScope.AddChild(v.Name, new ScriptVar(ex.Message));
+                        }
+
+
+                        var oldLex = currentLexer;
+                        var newLex = new ScriptLex(catchBlock.Var.String);
+                        currentLexer = newLex;
+
+                        scopes.PushBack(catchScope);
+
+                        Block(ref execute);
+
+                        scopes.PopBack();
+
+                        execute = true;
+
+                        currentLexer = oldLex;
+                    }
+                    else
+                    {
+                        throw new ScriptException(ex.Message, ex);
+                    }
+                }
+                finally
+                {
+                    if(finallyBlock != null)
+                    {
+                        var oldLex = currentLexer;
+                        var newLex = new ScriptLex(finallyBlock.Var.String);
+                        currentLexer = newLex;
+
+                        Block(ref execute);
+
+                        execute = true;
+
+                        currentLexer = oldLex;
+                    }
+                }
+
+                currentLexer = originalLexer;
+            }
+            else if(currentLexer.TokenType == ScriptLex.LexTypes.RThrow)
+            {
+                currentLexer.Match(ScriptLex.LexTypes.RThrow);
+
+                var message = string.Empty;
+
+                if (currentLexer.TokenType == (ScriptLex.LexTypes)';')
+                {
+                    currentLexer.Match((ScriptLex.LexTypes)';');
+                } 
+                else
+                {
+
+                    var res = Base(ref execute);
+                    message = res.Var.String;
+                }
+
+                throw new JITException(message);
+            }
             else 
             {
                 //execute a basic statement

diff --git a/DScript/ScriptEngine.cs b/DScript/ScriptEngine.cs
@@ -316,8 +316,13 @@ private ScriptVarLink FindInParentClasses(ScriptVar obj, string name)
 
         private ScriptVarLink ParseFunctionDefinition()
         {
-            currentLexer.Match(ScriptLex.LexTypes.RFunction);
-            var funcName = String.Empty;
+            return ParseDefinition(ScriptLex.LexTypes.RFunction);
+        }
+
+        private ScriptVarLink ParseDefinition(ScriptLex.LexTypes lexType)
+        {
+            currentLexer.Match(lexType);
+            var funcName = string.Empty;
 
             //named function
             if (currentLexer.TokenType == ScriptLex.LexTypes.Id)
@@ -327,7 +332,11 @@ private ScriptVarLink ParseFunctionDefinition()
             }
 
             var funcVar = new ScriptVarLink(new ScriptVar(null, ScriptVar.Flags.Function), funcName);
-            ParseFunctionArguments(funcVar.Var);
+
+            if (lexType == ScriptLex.LexTypes.RFunction || lexType == ScriptLex.LexTypes.RCatch)
+            {
+                ParseFunctionArguments(funcVar.Var);
+            }
 
             var funcBegin = currentLexer.TokenStart;
             var noExecute = false;

diff --git a/DScript/ScriptLex.cs b/DScript/ScriptLex.cs
@@ -126,6 +126,10 @@ public enum LexTypes
             RUndefined,
             RNew,
             RTypeOf,
+            RTry,
+            RCatch,
+            RFinally,
+            RThrow,
             RListEnd
         }
 
@@ -249,6 +253,10 @@ public void GetNextToken()
                     case "undefined": TokenType = LexTypes.RUndefined; break;
                     case "new": TokenType = LexTypes.RNew; break;
                     case "typeof": TokenType = LexTypes.RTypeOf; break;
+                    case "try": TokenType = LexTypes.RTry; break;
+                    case "catch": TokenType = LexTypes.RCatch; break;
+                    case "finally": TokenType = LexTypes.RFinally; break;
+                    case "throw": TokenType = LexTypes.RThrow; break;
                 }
             }
             else if (CurrentChar.IsNumeric()) //Numbers

diff --git a/README.md b/README.md
@@ -1,7 +1,7 @@
 DScript
 =======
 
-Open sourced object oriented Javascript based scripting language implemented in C#.
+Open sourced, object oriented, Javascript based, extendable scripting language implemented in C#.
 
 ***Example***
 
@@ -26,6 +26,7 @@ Open sourced object oriented Javascript based scripting language implemented in
 - Method scope
 - Arithmetic
 - Eval/Exec
+- Basic exception handling (try/catch/finally/throw)
 - ...more
 
 ***Arithmetic operators***
@@ -65,3 +66,6 @@ Open sourced object oriented Javascript based scripting language implemented in
   - tan
   - tanh
 - Random number library
+- JSON
+  - parse
+  - stringify