hakorune/docs/development/current/phase_9_78e_summary.md

Phase 9.78e: Dynamic Method Dispatch Implementation Summary

🎯 Overview

Phase 9.78e aimed to implement dynamic method dispatch through the call_method trait method to unify method calling across all Box types.

✅ Completed Tasks

1. NyashBox Trait Enhancement

• Added call_method to the NyashBox trait in src/box_trait.rs
• Default implementation returns MethodNotFound error
• Signature: fn call_method(&mut self, method_name: &str, args: Vec<NyashValue>) -> Result<NyashValue, RuntimeError>

2. StringBox Implementation

• Implemented call_method in src/boxes/string_box.rs
• Supports all StringBox methods:
  • type_name(), equals(), length()
  • concat(), split(), toUpperCase(), toLowerCase()
  • trim(), indexOf(), replace(), charAt(), substring()
• Includes argument validation and proper error handling

3. InstanceBox Implementation

• Implemented call_method in src/instance_v2.rs with delegation pattern:
  1. First checks user-defined methods
  2. Delegates to inner box for builtin methods
  3. Handles InstanceBox-specific methods (getField, setField, hasMethod)
• Enables transparent method calls on wrapped builtin boxes

4. Error Type Updates

• Added new RuntimeError variants:
  • MethodNotFound { method_name: String, type_name: String }
  • FieldNotFound { field_name: String, class_name: String }

5. Interpreter Integration (Partial)

• Added call_method integration in src/interpreter/expressions/calls.rs
• Implemented type conversion logic for Box to NyashValue
• Added debug output for tracking method dispatch flow

🚧 Challenges Encountered

1. Type Conversion Complexity

• Converting between Box<dyn NyashBox>, Arc<Mutex<dyn NyashBox>>, and NyashValue
• Current workaround: Direct type-based conversion for basic types

2. Binary Compilation Issues

• Several unrelated compilation errors in the binary prevent full testing
• Library builds successfully with call_method implementation

3. Architecture Considerations

• The current Box/NyashValue dual system creates friction
• Future consideration: Unified value representation system

📋 Test Results

• Basic StringBox creation and string operations work correctly
• Method calls currently fall back to legacy dispatch system
• Call_method infrastructure is in place but needs full integration

🔮 Next Steps

Immediate Tasks:

1. Fix binary compilation errors to enable full testing
2. Complete NyashValue/Box type conversion helpers
3. Implement call_method for remaining builtin Box types

Long-term Improvements:

1. Consider unified value representation to simplify type conversions
2. Optimize method dispatch performance
3. Add comprehensive test coverage for all Box types

💡 Key Insights

• The delegation pattern in InstanceBox successfully enables method calls on wrapped boxes
• Dynamic dispatch through call_method provides a clean abstraction for method calling
• Type conversion between the Box trait system and NyashValue remains a key challenge

📝 Code Locations

• Trait definition: src/box_trait.rs:124-130
• StringBox impl: src/boxes/string_box.rs:160-313
• InstanceBox impl: src/instance_v2.rs:197-263
• Interpreter integration: src/interpreter/expressions/calls.rs:230-288

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Phase 9.78e establishes the foundation for unified method dispatch across all Nyash Box types, with the core infrastructure successfully implemented and ready for expanded integration.