Fix NaturalArray assignment recursion causing LazyLoop stack overflow (without changing LazyLoop behavior)

README.md

@@ -26,6 +26,8 @@
 - [Why Coderive?](#why-coderive)
 - [Getting Started](#getting-started)
 - [Language Features](#language-features)
+- [Latest in src](#latest-in-src)
+- [Validation Snapshot](#validation-snapshot)
 - [Examples](#examples)
 - [Web Playground](#web-playground)
 - [License](#license)
@@ -330,6 +332,39 @@ out(report)
 
 ---
 
+## Latest in src
+
+Recent `src/**/*.cod` programs and std modules now showcase:
+
+- **Unsafe pointers and fixed buffers** (`*T`, `T[n]`, `&`, `*`, pointer arithmetic) in `test/unsafe/*`.
+- **Static imports** for methods/fields in `test/staticimports*`.
+- **Lambda auto-currying** forms like `\(a) \(b) ...` plus classic tuple lambdas in `test/lambda/*`.
+- **Union + runtime type checks** via `int|text` and `is` in `test/typesliterals/*`.
+- **Range and formula optimizations** across lazy arrays, multi-array dependencies, and recurrence tests.
+- **Expanded standard library coverage** in `std/math`, `std/scimath`, and `std/json` with comprehensive demo suites.
+
+---
+
+## Validation Snapshot
+
+Current demo validation status from `src/main/cod/demo/src/main/test`:
+
+- `CodP-TAC parity runner` (`cod.runner.CodPTACParityRunner`, excluding `*Invalid*.cod`): **48/48 passed**.
+- `LazyLoop.cod` parity: **passed**.
+- Direct `CommandRunner` scans (same non-invalid set) highlight remaining runtime limitations:
+  - `LazyLoop.cod` previously hit a stack overflow error during conditional-formula-style parity value reads. This update fixes the runtime recursion issue without changing demo behavior.
+  - `ConditionalFormulaOptimization.cod` can still trigger a stack overflow error.
+  - Input-driven demos (`Interactive.cod`, `IO.cod`, `Parity.cod`) fail without real stdin values.
+  - `HelloWorld.cod`, `JsonStandardLibraryComprehensive.cod`, `OOPConstructor.cod`, `SuperThis.cod`, and `test/unsafe/*` currently expose parser/runtime issues when executed directly via `CommandRunner`.
+
+Checked invalid demos (`*Invalid*.cod`) confirm currently unsupported/invalid patterns:
+
+- Reassigning constants after declaration.
+- Declaring constants without initializer.
+- Malformed self-call forms (`<~` without call target/parentheses, or invalid level-call syntax in methods).
+
+---
+
 ## Examples
 
 The [`examples/`](examples/) directory has ready-to-run programs:

src/main/java/cod/interpreter/handler/AssignmentHandler.java

@@ -189,7 +189,7 @@ private Object handleIndexAssignment(IndexAccess indexAccess, Object newValue, E
                 NaturalArray natural = (NaturalArray) arrayObj;
                 long index = expressionHandler.toLongIndex(indexObj);
                 ensureNoActiveBorrow(arrayObj, index, ctx);
-                Object previous = natural.get(index);
+                Object previous = natural.peekMaterialized(index);
                 natural.set(index, newValue);
                 ctx.trackValueReplacement(previous, newValue);
                 return newValue;

src/main/java/cod/range/NaturalArray.java

@@ -773,11 +773,7 @@ public Object get(long index) {
             index = size + index;
         }
 
-        try {
-            checkBounds(index);
-        } catch (ProgramError e) {
-            throw e;
-        }
+        checkBounds(index);
 
         // ========== TRACKING ==========
         if (tracked) {
@@ -879,6 +875,27 @@ public Object get(long index, boolean withConversion) {
         return value;
     }
 
+    /**
+     * Returns a previously materialized value for an index without triggering
+     * formula evaluation.
+     */
+    public Object peekMaterialized(long index) {
+        if (index < 0) {
+            long size = size();
+            index = size + index;
+        }
+
+        checkBounds(index);
+
+        if (isMutable && cache != null && cache.containsKey(index)) {
+            return cache.get(index);
+        }
+        if (computedCache != null && computedCache.containsKey(index)) {
+            return computedCache.get(index);
+        }
+        return null;
+    }
+
     // Convert value to string based on its type
     private Object convertToString(Object value) {
         if (value == null) return "none";