Implements efficient reactive conditionals that pre-render branches once
and swap DOM nodes without recreation, enabling fast switching with
thousands of elements.
Key Fixes:
- Runtime now calls reevaluate_conditional_*() on signal changes
- Match/case swap logic uses phi nodes to load correct old case
- Previously hardcoded case_0 as old value, causing accumulation
- Branch render functions now wrap all content in container div
Implementation:
- Pre-render both if/else branches at init
- Store roots in globals (@cond_N_then_root, @cond_N_else_root)
- On signal change, swap DOM nodes via js_replace_at_marker()
- Match statements use switch/phi pattern to select old case
Tests:
- Added test_reactive_conditionals.py (5 new tests)
- Updated test_llvm_codegen_conditional.py for reactive infrastructure
- All 35 tests passing
Performance: No re-rendering on switches, perfect for dynamic content.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
