see ref values

Author: chrisbeamable

FadeBasic/CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Debugger would emit exit event during partial budget runs. 
 - Debugger can render `byte` variables.
 - Debugger can set non `int` and non `float` values.
+- Debugger can discovery variables declared through `ref` commands, such as 
+  `INC` or `INPUT`
 - Commands with `ref` parameters can access globally scoped variables.
 
 ### Added

FadeBasic/FadeBasic/Ast/ExpressionNode.cs

@@ -360,9 +360,12 @@ public class LiteralStringExpression : AstNode, ILiteralNode
 
         public LiteralStringExpression(Token token) : base(token)
         {
-            
             value = token.raw.Substring(1, token.raw.Length - 2); // account for quotes
         }
+        public LiteralStringExpression(Token token, string value) : base(token)
+        {
+            this.value = value;
+        }
 
 
         protected override string GetString()

FadeBasic/FadeBasic/Virtual/Compiler.cs

@@ -1360,7 +1360,7 @@ private void Compile(AddressExpression expression)
                             variable = refNode.variableName,
                             type = new TypeReferenceNode(refNode.DefaultTypeByName, refNode.startToken)
                         };
-                        Compile(fakeDeclStatement);
+                        Compile(fakeDeclStatement, includeDefaultInitializer: true);
                         if (!scope.TryGetVariable(refNode.variableName, out variable))
                         {
                             throw new Exception(
@@ -1575,7 +1575,7 @@ public void Compile(CommandStatement commandStatement)
 
         }
 
-        public void Compile(DeclarationStatement declaration)
+        public void Compile(DeclarationStatement declaration, bool includeDefaultInitializer=false)
         {
             /*
              * the declaration tells us that we need a register
@@ -1757,6 +1757,38 @@ public void Compile(DeclarationStatement declaration)
                 };
                 Compile(fakeAssignment);
             }
+            else if (includeDefaultInitializer)
+            {
+
+                if (declaration.ranks == null)
+                {
+                    switch (tc)
+                    {
+                        case TypeCodes.STRUCT:
+                            // TODO: it isn't possible to pass structs as refs atm, but if it was, this would be a problem. 
+                            break;
+                        case TypeCodes.STRING: // TODO: handle the empty string?
+                            // if the variable is a string, then always assign it to the empty string, which will get interned. 
+                            var fadeStrAssignment = new AssignmentStatement
+                            {
+                                expression = new LiteralStringExpression(declaration.startToken, ""),
+                                variable = new VariableRefNode(declaration.startToken, declaration.variable)
+                            };
+                            Compile(fadeStrAssignment);
+                            break;
+                        default:
+                            // if the variable is a primitive, then always assign it to a default value.
+                            var fakeAssignment = new AssignmentStatement
+                            {
+                                expression = new LiteralIntExpression(declaration.startToken, 0),
+                                variable = new VariableRefNode(declaration.startToken, declaration.variable)
+                            };
+                            Compile(fakeAssignment);
+                            break;
+                    }
+                    
+                }
+            }
         }
 
         public void PushAddress(ArrayIndexReference arrayRefNode)

FadeBasic/Tests/DebuggerTests.cs

@@ -77,6 +77,8 @@ dim x(3,5) as vec
     }
 
     [TestCase("x# = 4.2", "x#+1", "5.2")]
+    [TestCase("inc x", "x", "1")]
+    [TestCase("tuna x$", "x$", "tuna")]
     [TestCase("x = 4", "x+1", "5")]
     [TestCase(@"
 x = 1