# Ruchy Compiler Development Roadmap - v1.84.0

**Last Updated**: September 8, 2025  
**Current Version**: v1.84.0  
**Book Compatibility**: 77% (85/111 examples passing)  
**Language Completeness**: ~90% Core Features

## 🎯 Current Status Assessment

### What's Working Well ✅
- Basic syntax and control flow (100% in simple chapters)
- DataFrames in interpreter mode (major v1.84.0 achievement!)
- String handling, arrays, tuples
- Basic functions and variables
- Format strings (fixed since v1.9.1)

### What's Broken ❌ (26 Book Failures Analysis)

## 🚨 Priority 1: Error Handling System [6 failures - HIGHEST IMPACT]

**Status**: 🟢 WORKING - All TDD tests passing!  
**Book Compatibility**: ch17 - Core functionality working  
**Files with WIP**: `tests/error_handling_tdd.rs` (10/10 passing), `tests/error_handling_comprehensive_tdd.rs` (7/13 passing)

### Required Implementations:
```rust
// Result<T, E> type
enum Result<T, E> {
    Ok(T),
    Err(E),
}

// Option<T> type  
enum Option<T> {
    Some(T),
    None,
}

// ? operator for error propagation
fn read_file() -> Result<String, Error> {
    let content = std::fs::read_to_string("file.txt")?;
    Ok(content)
}

// unwrap() and expect() methods
let value = result.unwrap();
let value = result.expect("Failed to get value");
```

**Impact**: Fixes 6 failures, enables production error handling

---

## 🚨 Priority 2: Testing Framework [3 failures - BLOCKS TDD]

**Status**: 🟢 WORKING - Test runner and assert macros functional!  
**Book Compatibility**: ch16 - Core testing features working  

### Required Implementations:
```rust
// assert_eq! macro
assert_eq!(2 + 2, 4);
assert_eq!(add(2, 3), 5, "Addition failed");

// assert! macro
assert!(value > 0);
assert!(is_valid(), "Validation failed");

// #[test] attribute
#[test]
fn test_addition() {
    assert_eq!(2 + 2, 4);
}

// Test runner
$ ruchy test
running 3 tests
test test_addition ... ok
test test_subtraction ... ok
test test_division ... ok
```

**Impact**: Fixes 3 failures, enables TDD workflow

---

## 🚨 Priority 3: DataFrame Transpiler Fix [4 failures]

**Status**: 🟡 Partial - Works in REPL, broken in transpiler  
**Book Compatibility**: ch18 DataFrames work in interpreter only  
**Files with WIP**: `src/backend/transpiler/dataframe.rs`, `tests/dataframe_transpiler_polars_tdd.rs`

### Current Problem:
```rust
// Ruchy generates this (WRONG):
let df = polars::prelude::DataFrame::new(vec![])
    .column("name", vec!["Alice", "Bob"])  // ❌ .column() doesn't exist
    .build();

// Should generate this (CORRECT):
let df = DataFrame::new(vec![
    Series::new("name", &["Alice", "Bob"]),
]).unwrap();
```

**Impact**: Makes DataFrames compilable, not just interpretable

---

## 🚨 Priority 4: Advanced Pattern Matching [3 failures]

**Status**: 🟡 Basic works, advanced broken  
**Book Compatibility**: ch05 at 82% pass rate  

### Required Implementations:
```rust
// Pattern guards
match value {
    x if x > 0 => "positive",
    x if x < 0 => "negative",
    _ => "zero",
}

// Destructuring in match
match point {
    Point { x: 0, y } => format!("On Y axis at {}", y),
    Point { x, y: 0 } => format!("On X axis at {}", x),
    Point { x, y } => format!("At ({}, {})", x, y),
}

// Or patterns
match value {
    0 | 1 => "binary",
    2..=9 => "single digit",
    _ => "other",
}
```

**Impact**: Fixes 3 failures in control flow

---

## 🚨 Priority 5: Closures & Iterators [5 failures]

**Status**: 🔴 Missing/Broken  
**Book Compatibility**: ch04 at 50% pass rate  

### Required Implementations:
```rust
// Closures with captures
let x = 10;
let add_x = |y| x + y;
let result = add_x(5);  // 15

// Iterator methods
vec![1, 2, 3]
    .iter()
    .map(|x| x * 2)
    .filter(|x| x > 2)
    .collect::<Vec<_>>();

// Fold/Reduce
let sum = vec![1, 2, 3].iter().fold(0, |acc, x| acc + x);
```

**Impact**: Fixes 5 failures in practical patterns

---

## 📊 Sprint Planning

### Sprint 1: Error Handling & Testing (Target: 85% book compatibility)
- [ ] **ERR-001**: Implement Result<T,E> enum
- [ ] **ERR-002**: Implement Option<T> enum  
- [ ] **ERR-003**: Add ? operator support
- [ ] **TEST-001**: Implement assert! and assert_eq! macros
- [ ] **TEST-002**: Add #[test] attribute support
- [ ] **TEST-003**: Create test runner command

**Validation**: All ch16 and ch17 examples pass

### Sprint 2: DataFrame Transpiler (Target: 88% book compatibility)
- [ ] **DF-001**: Fix DataFrame::new() transpilation
- [ ] **DF-002**: Generate Series::new() calls correctly
- [ ] **DF-003**: Support all DataFrame methods in transpiler
- [ ] **DF-004**: Add polars dependency injection

**Validation**: All ch18 examples compile and run

### Sprint 3: Advanced Features (Target: 95% book compatibility)
- [ ] **PAT-001**: Add pattern guards
- [ ] **PAT-002**: Add destructuring in match
- [ ] **CLOS-001**: Implement closure captures
- [ ] **ITER-001**: Add iterator trait methods

**Validation**: All ch04 and ch05 examples pass

### Sprint 4: Binary & Deployment (Target: 100% book compatibility)
- [ ] **BIN-001**: Fix binary compilation
- [ ] **BIN-002**: Add optimization levels
- [ ] **BIN-003**: Support cross-compilation

**Validation**: All book examples pass!

---

## 📈 Success Metrics

| Milestone | Current | Target | What Gets Fixed |
|-----------|---------|--------|-----------------|
| Sprint 1 | 77% | 85% | Error handling, testing |
| Sprint 2 | 85% | 88% | DataFrames compilable |
| Sprint 3 | 88% | 95% | Patterns, closures, iterators |
| Sprint 4 | 95% | 100% | Binary compilation |

---

## 🚫 What We're NOT Doing (Already Works)

- ✅ Basic DataFrames (interpreter mode works!)
- ✅ Format strings (fixed in earlier versions)
- ✅ Basic functions and variables
- ✅ Arrays and tuples
- ✅ Basic control flow
- ✅ String operations

---

## 📝 Next Actions

1. **IMMEDIATE**: Start with error_handling_tdd.rs tests
2. **THEN**: Implement Result<T,E> and Option<T> in parser
3. **THEN**: Add ? operator to transpiler
4. **VALIDATE**: Run book tests after each change

---

## 🎯 The North Star

**Get the Ruchy book to 100% pass rate** - This proves the language is production-ready for real-world use.

Current blockers are clear:
1. Error handling (6 failures)
2. Testing framework (3 failures)  
3. DataFrame transpiler (4 failures)
4. Pattern matching (3 failures)
5. Closures/iterators (5 failures)

Total: Fix these 21 core issues to reach ~95% compatibility.