refactor: Move swap operator implementation to own lowerer

NewSource/SocordiaC/Compilation/Listeners/Body/BinaryOperatorListener.cs

@@ -14,10 +14,6 @@ protected override void ListenToNode(BodyCompilation context, BinaryOperatorExpr
         {
             EmitAssignment(context, node);
         }
-        else if (node.Operator is "<->")
-        {
-            EmitSwap(context, node);
-        }
     }
 
     private void EmitAssignment(BodyCompilation context, BinaryOperatorExpression node)
@@ -37,38 +33,5 @@ private void EmitAssignment(BodyCompilation context, BinaryOperatorExpression no
         }
     }
 
-    private void EmitSwap(BodyCompilation context, BinaryOperatorExpression node)
-    {
-        //ToDo: test swap operator
-        var lvalue = context.Scope.GetFromNode(node.Left);
-        var rvalue = context.Scope.GetFromNode(node.Right);
-
-        if (lvalue is ScopeItem { IsMutable: false } si)
-        {
-            node.Left.AddError("Variable '" + si.Name + "' is not mutable");
-            return;
-        }
-
-        if (rvalue is ScopeItem { IsMutable: false } si2)
-        {
-            node.Right.AddError("Variable '" + si2.Name + "' is not mutable");
-            return;
-        }
-
-        //ToDo: add check if types are compatible
-
-        //todo: generalize to allow swapping of fields and parameters too
-        if (lvalue is VariableScopeItem vsi && rvalue is VariableScopeItem vsi2)
-        {
-            var temp = context.Builder.Method.CreateVar(vsi.Type);
-            context.Builder.CreateStore(temp, vsi.Slot);
-            context.Builder.CreateStore(vsi.Slot, vsi2.Slot);
-            context.Builder.CreateStore(vsi2.Slot, temp);
-        }
-    }
-
-    protected override bool ShouldListenToChildren(BodyCompilation context, BinaryOperatorExpression node)
-    {
-        return false;
-    }
+    protected override bool ShouldListenToChildren(BodyCompilation context, BinaryOperatorExpression node) => false;
 }

NewSource/SocordiaC/Compilation/Listeners/Body/Lowering/AssignmentsLowerer.cs

@@ -23,4 +23,4 @@ public class AssignmentsLowerer : Replacer<AstNode, BinaryOperatorExpression>
             new BinaryOperatorExpression(newOperator, node.Left, node.Right)
         );
     }
-}
+}

NewSource/SocordiaC/Compilation/Listeners/Body/Lowering/Lowerer.cs

@@ -8,5 +8,9 @@ public static class Lowerer
     public static readonly Pipeline<AstNode> Pipeline =
         Pipeline<AstNode>
             .Build(
-                builder => { builder.AddStage<AssignmentsLowerer>(); });
+                builder =>
+                {
+                    builder.AddStage<AssignmentsLowerer>();
+                    builder.AddStage<SwapLowerer>();
+                });
 }

NewSource/SocordiaC/Compilation/Listeners/Body/Lowering/SwapLowerer.cs

@@ -0,0 +1,22 @@
+using MrKWatkins.Ast.Processing;
+using Socordia.CodeAnalysis.AST;
+using Socordia.CodeAnalysis.AST.Expressions;
+
+namespace SocordiaC.Compilation.Listeners.Body.Lowering;
+
+public class SwapLowerer : Replacer<AstNode, BinaryOperatorExpression>
+{
+    protected override AstNode? ReplaceNode(BinaryOperatorExpression node)
+    {
+        if (node.Operator != "<->") return node;
+
+        //todo: implement a swap by introducting a new temp variable and test it
+        var tmpName = Utils.GenerateIdentifier();
+        var tmp = new VariableStatement(tmpName, node.Left.Type, node.Left, false);
+
+        var left = new BinaryOperatorExpression("=", node.Left, node.Right);
+        var right = new BinaryOperatorExpression("=", node.Right, new Identifier(tmpName));
+
+        return new Block([tmp, left, right]);
+    }
+}

NewSource/SocordiaC/Compilation/Utils.cs

@@ -163,4 +163,20 @@ public static void EmitAnnotations(Declaration declaration, ModuleEntity entity)
     {
         foreach (var annotation in declaration.Annotations) EmitAnnotation(annotation, entity);
     }
+
+    public static string GenerateIdentifier()
+    {
+        var sb = new StringBuilder();
+        sb.Append("<tmp>_");
+
+        const string ALPHABET = "abcdefhijklmnopqrstABCDEFGHIJKLMNOPQRSTUVWXYZ&%$";
+        var random = new Random();
+
+        for (var i = 0; i < random.Next(5, 9); i++)
+        {
+            sb.Append(ALPHABET[random.Next(ALPHABET.Length)]);
+        }
+
+        return sb.ToString();
+    }
 }

Source/Backlang.Driver/Utils.cs

@@ -6,19 +6,7 @@ namespace Backlang.Driver;
 
 public static class Utils
 {
-    public static string GenerateIdentifier()
-    {
-        var sb = new StringBuilder();
-        const string ALPHABET = "abcdefhijklmnopqrstABCDEFGHIJKLMNOPQRSTUVWXYZ&%$";
-        var random = new Random();
-
-        for (var i = 0; i < random.Next(5, 9); i++)
-        {
-            sb.Append(ALPHABET[random.Next(ALPHABET.Length)]);
-        }
-
-        return sb.ToString();
-    }
+
 
     public static void AddCompilerGeneratedAttribute(TypeResolver binder, DescribedType type)
     {