Working Through a Milestone

Before Starting

1. Review the last commit: git show HEAD
2. Run tests to see current state: mise test
3. Read relevant test files in testcases/ to understand expected behavior
4. CRITICAL: Assess host interface sufficiency

- Review src/tclc.h (TclHostOps) to understand available primitives - Determine if the feature can be implemented using existing ops - If TclHostOps needs to be extended: STOP IMMEDIATELY and inform the user - Do not proceed until you have received explicit approval and direction

Implementation Loop

For each failing test:

1. Identify what's missing - parse test output to understand the gap
2. C interpreter changes (in src/):

- Create new builtin_*.c file if adding a command - Add declarations to internal.h - Register command in interp.c builtins table - Implement using TclHostOps primitives only

1. Go host changes (in interp/):

- Implement callbacks in callbacks.go - Add state to Interp struct in tclc.go if needed - Follow shimmering rules in interp/CLAUDE.md

1. Run tests: mise test
2. Iterate until tests pass

Key Patterns

• List operations mutate: Use ops->list.from() to copy before iterating
• String lengths: Count carefully, don't include null terminator
• Shimmering: Use Get*() methods in Go for type conversion, never access Object fields directly
• Error messages: Match TCL's exact format (check test expectations)

After All Tests Pass

1. Run tests multiple times to verify stability
2. Commit with detailed message explaining:

- What was implemented - Key implementation details - Important learnings for future work

1. Use the format from CLAUDE.md (heredoc, co-author line)

File Checklist for New Commands

• src/builtin_<cmd>.c - implementation
• src/internal.h - declaration
• src/interp.c - registration
• interp/callbacks.go - host callbacks (if new ops needed)
• interp/tclc.go - state/structs (if needed)