TRACKING.md

Master TODO & Incomplete Features

This document tracks all incomplete features, known limitations, and remaining tasks for the Crustty C Interpreter.

🔴 Critical Missing Features / Bugs

• Complex Member Access: Implementation needed for nested field access via pointers (e.g., ptr->nested.field).
• Pointer Arithmetic: Full support for mixing pointers and dereferences in arithmetic expressions (e.g., x + *ptr).
• Type Checking:
  • Mixed char/int arithmetic behavior needs verification.
  • Strict type checking for assignments and function calls.
• Printf Support:
  • Basic specifiers: %d, %u, %x, %c, %s, %%.
  • Missing width/precision modifiers.
• Goto/Label:
  • Forward gotos within the same function (the goto cleanup pattern).
  • Backward gotos (jumping to a label before the goto statement).
  • Goto into nested blocks.

🟡 TUI & Usability Improvements

• Performance:
  • Implement pagination/windowing for Stack and Heap panes (currently renders all items, potentially slow).
  • Optimize large memory snapshot rendering.
• Display Limits:
  • Handle deep or cyclic struct references in variables view (verify recursion limits).
• Input Handling:
  • Verify scrolling behavior when stepping backwards (auto-scroll to active line).
  • Shift+Tab (BackTab) for reverse pane cycling.

🟢 Integration & Polish

• CLI/Main:
  • Ensure main.rs gracefully transitions to TUI.
  • Better error reporting for runtime errors without TUI mode.
• Standard Library:
  • Add memset, memcpy, strcpy built-ins.
  • Support NULL macro properly in all contexts.
• Error Handling:
  • Use-after-free errors now produce RuntimeError::UseAfterFree with proper address instead of generic InvalidMemoryOperation.

🧪 Testing & Verification

• CI Limitations: Tests requiring TTY/Interactive TUI cannot run in CI.
• Integration Scenarios:
  • Full run-through of examples/default.c checking for memory leaks.
• Edge Cases:
  • Stack overflow detection (recursion limit).
  • Zero-size allocations.

🧊 Backlog / Future

• Parser: Switch to nom or similar if hand-written parser becomes unmaintainable.
• Snapshot Optimization: Implement copy-on-write instead of full cloning for memory efficiency.
• Save/Load: Capability to save execution trace to file.

Completed Cleanup

• Removed unused RuntimeError::Generic variant and RuntimeError::format() method.
• Removed unused Theme.bg field.
• Removed unused MockTerminal::println, delete_output_from_line, clear methods.
• Removed unused SnapshotManager::latest, count, clear methods.