guard against no initializer

Stepami · Oct 16, 2023 · 2cc2a53 · 2cc2a53
1 parent a8ed4d0
commit 2cc2a53
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Showing 5 changed files with 31 additions and 18 deletions.
diff --git a/Interpreter.Lib/FrontEnd/TopDownParse/Impl/Parser.cs b/Interpreter.Lib/FrontEnd/TopDownParse/Impl/Parser.cs
@@ -368,7 +368,13 @@ private void AddToDeclaration(LexicalDeclaration declaration)
     {
         var ident = Expect("Ident");
         var identRef = new IdentifierReference(ident.Value) { Segment = ident.Segment };
-        AssignmentExpression assignment = null;
+        var assignment = new AssignmentExpression(
+                new MemberExpression(identRef),
+                new ImplicitLiteral(
+                    new TypeIdentValue(
+                        new IdentifierReference("undefined"))))
+            { Segment = ident.Segment };
+
         if (CurrentIs("Assign"))
         {
             var assignSegment = Expect("Assign").Segment;

diff --git a/Interpreter.Lib/IR/Ast/Impl/Nodes/Declarations/AfterTypesAreLoaded/LexicalDeclaration.cs b/Interpreter.Lib/IR/Ast/Impl/Nodes/Declarations/AfterTypesAreLoaded/LexicalDeclaration.cs
@@ -8,12 +8,12 @@ namespace Interpreter.Lib.IR.Ast.Impl.Nodes.Declarations.AfterTypesAreLoaded;
 
 public class LexicalDeclaration : AfterTypesAreLoadedDeclaration
 {
-    public bool Readonly { get; }
+    public bool ReadOnly { get; }
     public List<AssignmentExpression> Assignments { get; }
 
-    public LexicalDeclaration(bool @readonly)
+    public LexicalDeclaration(bool readOnly)
     {
-        Readonly = @readonly;
+        ReadOnly = readOnly;
         Assignments = new();
     }
 
@@ -27,7 +27,7 @@ public override IEnumerator<AbstractSyntaxTreeNode> GetEnumerator() =>
         Assignments.GetEnumerator();
 
     protected override string NodeRepresentation() =>
-        Readonly ? "const" : "let";
+        ReadOnly ? "const" : "let";
 
     public override AddressedInstructions Accept(InstructionProvider visitor) =>
         visitor.Visit(this);

diff --git a/Interpreter.Lib/IR/CheckSemantics/Exceptions/ConstWithoutInitializer.cs b/Interpreter.Lib/IR/CheckSemantics/Exceptions/ConstWithoutInitializer.cs
diff --git a/Interpreter.Lib/IR/CheckSemantics/Exceptions/DeclarationWithoutInitializer.cs b/Interpreter.Lib/IR/CheckSemantics/Exceptions/DeclarationWithoutInitializer.cs
@@ -0,0 +1,11 @@
+using System.Diagnostics.CodeAnalysis;
+using Interpreter.Lib.IR.Ast.Impl.Nodes.Expressions.PrimaryExpressions;
+
+namespace Interpreter.Lib.IR.CheckSemantics.Exceptions;
+
+[ExcludeFromCodeCoverage]
+public class DeclarationWithoutInitializer : SemanticException
+{
+    public DeclarationWithoutInitializer(IdentifierReference ident, bool readOnly) :
+        base(ident.Segment, $"'{(readOnly ? "const" : "let")}' without initializer: {ident.Name}") { }
+}
diff --git a/Interpreter.Lib/IR/CheckSemantics/Visitors/DeclarationVisitor.cs b/Interpreter.Lib/IR/CheckSemantics/Visitors/DeclarationVisitor.cs
@@ -1,5 +1,7 @@
 using Interpreter.Lib.IR.Ast;
 using Interpreter.Lib.IR.Ast.Impl.Nodes.Declarations.AfterTypesAreLoaded;
+using Interpreter.Lib.IR.Ast.Impl.Nodes.Expressions.ComplexLiterals;
+using Interpreter.Lib.IR.Ast.Impl.Nodes.Expressions.PrimaryExpressions;
 using Interpreter.Lib.IR.CheckSemantics.Exceptions;
 using Interpreter.Lib.IR.CheckSemantics.Types;
 using Interpreter.Lib.IR.CheckSemantics.Variables.Symbols;
@@ -26,14 +28,19 @@ public Unit Visit(LexicalDeclaration visitable)
         {
             if (visitable.SymbolTable.ContainsSymbol(assignment.Destination.Id))
                 throw new DeclarationAlreadyExists(assignment.Destination.Id);
-            
+
             var destinationType = assignment.DestinationType?.BuildType(
                 assignment.SymbolTable) ?? "undefined";
+
+            if (destinationType == "undefined" &&
+                assignment.Source is ImplicitLiteral or ArrayLiteral { Expressions.Count: 0 })
+                throw new DeclarationWithoutInitializer(assignment.Destination.Id, visitable.ReadOnly);
+
             visitable.SymbolTable.AddSymbol(
                 new VariableSymbol(
                     assignment.Destination.Id,
                     destinationType,
-                    visitable.Readonly));
+                    visitable.ReadOnly));
         }
 
         return default;