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Dana Structs Cookbook - Real-World Patterns

Practical recipes for common struct patterns and use cases


Table of Contents

  1. Business Domain Models
  2. Data Processing Pipelines
  3. Configuration Management
  4. Summary

Business Domain Models

Customer Relationship Management (CRM)

struct Contact:
    id: str
    first_name: str
    last_name: str
    email: str
    phone: str
    company_id: str
    status: str  # "active", "inactive", "prospect"
    tags: list
    created_at: str

struct Company:
    id: str
    name: str
    industry: str
    size: str  # "startup", "small", "medium", "large", "enterprise"
    contacts: list
    revenue: float
    location: str

struct Deal:
    id: str
    contact_id: str
    company_id: str
    amount: float
    stage: str  # "prospect", "proposal", "negotiation", "closed_won", "closed_lost"
    probability: float
    close_date: str
    notes: str

# Business logic functions
def qualify_lead(contact: Contact, company: Company) -> str:
    # AI-powered lead qualification
    qualification = reason(
        "Assess lead quality based on contact and company information",
        context=[contact, company],
        format="json"
    )
    return qualification

def predict_deal_success(deal: Deal, company: Company, contact: Contact) -> float:
    # Predictive analysis
    prediction = reason(
        "Predict the probability of this deal closing successfully",
        context=[deal, company, contact],
        temperature=0.3  # More deterministic
    )

    # Extract probability from AI response
    if "%" in prediction:
        # Parse percentage
        percentage_str = prediction.split("%")[0].split()[-1]
        return float(percentage_str) / 100.0
    return deal.probability

def generate_follow_up_strategy(deal: Deal, contact: Contact) -> str:
    strategy = reason(
        f"Generate a follow-up strategy for a {deal.stage} stage deal",
        context=[deal, contact]
    )
    return strategy

# Usage patterns
def process_new_lead(contact_data: dict, company_data: dict) -> dict:
    # Create domain objects
    contact = Contact(
        id=contact_data.get("id"),
        first_name=contact_data.get("first_name"),
        last_name=contact_data.get("last_name"),
        email=contact_data.get("email"),
        phone=contact_data.get("phone", ""),
        company_id=company_data.get("id"),
        status="prospect",
        tags=[],
        created_at=get_current_timestamp()
    )

    company = Company(
        id=company_data.get("id"),
        name=company_data.get("name"),
        industry=company_data.get("industry"),
        size=company_data.get("size"),
        contacts=[],
        revenue=company_data.get("revenue", 0),
        location=company_data.get("location")
    )

    # AI-powered qualification
    qualification = contact.qualify_lead(company)

    # Create deal if qualified
    if "qualified" in qualification.lower():
        deal = Deal(
            id=generate_id("DEAL"),
            contact_id=contact.id,
            company_id=company.id,
            amount=estimate_deal_value(company),
            stage="prospect",
            probability=0.1,
            close_date=estimate_close_date(),
            notes=qualification
        )

        # Predict success probability
        predicted_probability = deal.predict_deal_success(company, contact)
        deal.probability = predicted_probability

        # Generate follow-up strategy
        strategy = deal.generate_follow_up_strategy(contact)

        return {
            "contact": contact,
            "company": company,
            "deal": deal,
            "qualification": qualification,
            "strategy": strategy,
            "status": "qualified"
        }

    return {
        "contact": contact,
        "company": company,
        "qualification": qualification,
        "status": "not_qualified"
    }

Financial Portfolio Management

struct Asset:
    symbol: str
    name: str
    asset_type: str  # "stock", "bond", "etf", "crypto"
    current_price: float
    currency: str
    market_cap: float
    sector: str

struct Position:
    asset: Asset
    quantity: float
    average_cost: float
    current_value: float
    unrealized_gain_loss: float
    weight: float  # Portfolio weight percentage

struct Portfolio:
    id: str
    name: str
    owner_id: str
    positions: list
    total_value: float
    cash_balance: float
    risk_tolerance: str  # "conservative", "moderate", "aggressive"
    target_allocation: dict  # Sector/asset type targets

# Portfolio analysis functions
def calculate_portfolio_metrics(portfolio: Portfolio) -> dict:
    # Calculate real-time metrics
    total_value = portfolio.cash_balance
    total_gain_loss = 0.0

    for position in portfolio.positions:
        position.current_value = position.quantity * position.asset.current_price
        position.unrealized_gain_loss = position.current_value - (position.quantity * position.average_cost)
        total_value = total_value + position.current_value
        total_gain_loss = total_gain_loss + position.unrealized_gain_loss

    # Update portfolio total
    portfolio.total_value = total_value

    # Calculate weights
    for position in portfolio.positions:
        if total_value > 0:
            position.weight = (position.current_value / total_value) * 100

    return {
        "total_value": total_value,
        "total_gain_loss": total_gain_loss,
        "total_return_pct": (total_gain_loss / (total_value - total_gain_loss)) * 100 if total_value > total_gain_loss else 0,
        "cash_percentage": (portfolio.cash_balance / total_value) * 100 if total_value > 0 else 100
    }

def analyze_risk_exposure(portfolio: Portfolio) -> dict:
    # AI-powered risk analysis
    sector_exposure = {}
    asset_type_exposure = {}

    for position in portfolio.positions:
        # Sector exposure
        sector = position.asset.sector
        if sector not in sector_exposure:
            sector_exposure[sector] = 0
        sector_exposure[sector] = sector_exposure[sector] + position.weight

        # Asset type exposure
        asset_type = position.asset.asset_type
        if asset_type not in asset_type_exposure:
            asset_type_exposure[asset_type] = 0
        asset_type_exposure[asset_type] = asset_type_exposure[asset_type] + position.weight

    # AI risk assessment
    risk_analysis = reason(
        f"Analyze portfolio risk for {portfolio.risk_tolerance} investor",
        context=[sector_exposure, asset_type_exposure, portfolio.target_allocation]
    )

    return {
        "sector_exposure": sector_exposure,
        "asset_type_exposure": asset_type_exposure,
        "risk_analysis": risk_analysis,
        "diversification_score": calculate_diversification_score(sector_exposure)
    }

def generate_rebalancing_recommendations(portfolio: Portfolio) -> list:
    # Calculate current vs target allocation
    current_metrics = portfolio.calculate_portfolio_metrics()
    risk_analysis = portfolio.analyze_risk_exposure()

    recommendations = reason(
        "Generate portfolio rebalancing recommendations",
        context=[
            portfolio.target_allocation,
            risk_analysis["sector_exposure"],
            portfolio.risk_tolerance,
            current_metrics
        ]
    )

    return parse_recommendations(recommendations)

def optimize_tax_efficiency(portfolio: Portfolio, tax_year: str) -> dict:
    # Tax loss harvesting and optimization
    tax_optimization = reason(
        "Suggest tax-efficient portfolio moves for the current tax year",
        context=[portfolio.positions, tax_year]
    )

    return {
        "tax_loss_harvesting": extract_tax_loss_opportunities(portfolio),
        "optimization_suggestions": tax_optimization
    }

# Helper functions
def calculate_diversification_score(sector_exposure: dict) -> float:
    # Simple diversification score based on sector distribution
    if not sector_exposure:
        return 0.0

    # Higher score for more even distribution
    num_sectors = len(sector_exposure)
    ideal_weight = 100.0 / num_sectors

    variance_sum = 0.0
    for weight in sector_exposure.values():
        variance_sum = variance_sum + ((weight - ideal_weight) ** 2)

    # Convert to 0-100 score (lower variance = higher score)
    variance_penalty = variance_sum / (num_sectors * ideal_weight * ideal_weight)
    return max(0, 100 - (variance_penalty * 100))

def extract_tax_loss_opportunities(portfolio: Portfolio) -> list:
    opportunities = []
    for position in portfolio.positions:
        if position.unrealized_gain_loss < 0:
            opportunities.append({
                "symbol": position.asset.symbol,
                "loss_amount": abs(position.unrealized_gain_loss),
                "suggestion": f"Consider harvesting ${abs(position.unrealized_gain_loss):.2f} loss from {position.asset.symbol}"
            })
    return opportunities

# Usage example
def create_sample_portfolio() -> Portfolio:
    # Create assets
    apple = Asset(
        symbol="AAPL",
        name="Apple Inc.",
        asset_type="stock",
        current_price=175.50,
        currency="USD",
        market_cap=2800000000000,
        sector="Technology"
    )

    sp500 = Asset(
        symbol="SPY",
        name="SPDR S&P 500 ETF",
        asset_type="etf", 
        current_price=445.20,
        currency="USD",
        market_cap=400000000000,
        sector="Diversified"
    )

    # Create positions
    apple_position = Position(
        asset=apple,
        quantity=100,
        average_cost=150.00,
        current_value=0,  # Will be calculated
        unrealized_gain_loss=0,  # Will be calculated
        weight=0  # Will be calculated
    )

    spy_position = Position(
        asset=sp500,
        quantity=50,
        average_cost=420.00,
        current_value=0,
        unrealized_gain_loss=0,
        weight=0
    )

    # Create portfolio
    portfolio = Portfolio(
        id="PORT-001",
        name="Growth Portfolio",
        owner_id="USER-123",
        positions=[apple_position, spy_position],
        total_value=0,  # Will be calculated
        cash_balance=5000.00,
        risk_tolerance="moderate",
        target_allocation={
            "Technology": 30,
            "Diversified": 50,
            "Cash": 20
        }
    )

    return portfolio

# Complete workflow
def portfolio_analysis_workflow():
    # Create portfolio
    portfolio = create_sample_portfolio()

    # Calculate metrics
    metrics = portfolio.calculate_portfolio_metrics()
    log(f"Portfolio value: ${metrics['total_value']:,.2f}")
    log(f"Total return: {metrics['total_return_pct']:.2f}%")

    # Analyze risk
    risk_analysis = portfolio.analyze_risk_exposure()
    log(f"Diversification score: {risk_analysis['diversification_score']:.1f}/100")

    # Get recommendations
    recommendations = portfolio.generate_rebalancing_recommendations()
    for rec in recommendations:
        log(f"Recommendation: {rec}")

    # Tax optimization
    tax_analysis = portfolio.optimize_tax_efficiency("2024")
    log(f"Tax optimization: {tax_analysis['optimization_suggestions']}")

    return {
        "portfolio": portfolio,
        "metrics": metrics,
        "risk_analysis": risk_analysis,
        "recommendations": recommendations,
        "tax_analysis": tax_analysis
    }

Data Processing Pipelines

ETL Pipeline for Analytics

struct DataSource:
    id: str
    name: str
    type: str  # "database", "api", "file", "stream"
    connection_string: str
    format: str  # "json", "csv", "xml", "parquet"
    schema: dict
    last_updated: str

struct DataRecord:
    source_id: str
    record_id: str
    data: dict
    timestamp: str
    quality_score: float
    errors: list

struct ProcessingStage:
    name: str
    input_type: str
    output_type: str
    configuration: dict
    metrics: dict

struct Pipeline:
    id: str
    name: str
    sources: list
    stages: list
    destination: str
    schedule: str
    status: str  # "running", "stopped", "failed", "completed"
    last_run: str
    error_count: int

# Data extraction functions
def extract_from_source(source: DataSource, batch_size: int = 1000) -> list:
    log(f"Extracting data from {source.name} ({source.type})")

    extracted_records = []

    if source.type == "database":
        records = query_database(source.connection_string, batch_size)
    elif source.type == "api":
        records = fetch_from_api(source.connection_string, source.format)
    elif source.type == "file":
        records = read_file(source.connection_string, source.format)
    else:
        log(f"Unsupported source type: {source.type}", level="error")
        return []

    # Convert to DataRecord objects
    for record in records:
        data_record = DataRecord(
            source_id=source.id,
            record_id=generate_record_id(),
            data=record,
            timestamp=get_current_timestamp(),
            quality_score=0.0,  # Will be calculated
            errors=[]
        )
        extracted_records.append(data_record)

    log(f"Extracted {len(extracted_records)} records from {source.name}")
    return extracted_records

def validate_data_quality(record: DataRecord, source: DataSource) -> DataRecord:
    # Schema validation
    quality_issues = []
    quality_score = 100.0

    # Check required fields
    required_fields = source.schema.get("required", [])
    for field in required_fields:
        if field not in record.data or record.data[field] is None:
            quality_issues.append(f"Missing required field: {field}")
            quality_score = quality_score - 20

    # Data type validation
    field_types = source.schema.get("types", {})
    for field, expected_type in field_types.items():
        if field in record.data:
            actual_value = record.data[field]
            if not validate_type(actual_value, expected_type):
                quality_issues.append(f"Type mismatch for {field}: expected {expected_type}")
                quality_score = quality_score - 10

    # AI-powered quality assessment
    ai_quality_check = reason(
        "Assess data quality and identify potential issues",
        context=record.data,
        temperature=0.1  # Deterministic
    )

    if "issue" in ai_quality_check.lower() or "error" in ai_quality_check.lower():
        quality_issues.append(f"AI detected: {ai_quality_check}")
        quality_score = quality_score - 15

    # Update record
    record.quality_score = max(0, quality_score)
    record.errors = quality_issues

    return record

def transform_data(record: DataRecord, transformation_rules: dict) -> DataRecord:
    # Apply transformation rules
    transformed_data = record.data.copy()

    # Field mapping
    field_mappings = transformation_rules.get("field_mappings", {})
    for old_field, new_field in field_mappings.items():
        if old_field in transformed_data:
            transformed_data[new_field] = transformed_data.pop(old_field)

    # Data enrichment
    enrichment_rules = transformation_rules.get("enrichment", {})
    for field, rule in enrichment_rules.items():
        if rule == "uppercase":
            if field in transformed_data:
                transformed_data[field] = str(transformed_data[field]).upper()
        elif rule == "normalize_phone":
            if field in transformed_data:
                transformed_data[field] = normalize_phone_number(transformed_data[field])
        elif rule.startswith("ai_"):
            # AI-powered transformation
            ai_result = reason(
                f"Apply {rule} transformation to: {transformed_data.get(field)}",
                context=transformed_data
            )
            transformed_data[field] = ai_result

    # Create new record with transformed data
    transformed_record = DataRecord(
        source_id=record.source_id,
        record_id=record.record_id,
        data=transformed_data,
        timestamp=get_current_timestamp(),
        quality_score=record.quality_score,
        errors=record.errors
    )

    return transformed_record

def execute_pipeline(pipeline: Pipeline) -> dict:
    log(f"Starting pipeline execution: {pipeline.name}")
    pipeline.status = "running"
    pipeline.last_run = get_current_timestamp()

    all_records = []
    total_processed = 0
    total_errors = 0

    # Extract from all sources
    for source in pipeline.sources:
        try:
            records = extract_from_source(source)

            # Validate data quality
            validated_records = []
            for record in records:
                validated_record = record.validate_data_quality(source)
                if validated_record.errors:
                    total_errors = total_errors + len(validated_record.errors)
                validated_records.append(validated_record)

            all_records.extend(validated_records)
            total_processed = total_processed + len(records)

        except Exception as e:
            log(f"Error extracting from {source.name}: {e}", level="error")
            total_errors = total_errors + 1

    # Process through pipeline stages
    processed_records = all_records
    for stage in pipeline.stages:
        try:
            stage_config = stage.configuration

            if stage.name == "transform":
                transformed_records = []
                for record in processed_records:
                    transformed = record.transform_data(stage_config)
                    transformed_records.append(transformed)
                processed_records = transformed_records

            elif stage.name == "filter":
                filtered_records = apply_filters(processed_records, stage_config)
                processed_records = filtered_records

            elif stage.name == "aggregate":
                aggregated_records = apply_aggregations(processed_records, stage_config)
                processed_records = aggregated_records

            # Update stage metrics
            stage.metrics = {
                "records_in": len(all_records) if stage == pipeline.stages[0] else len(processed_records),
                "records_out": len(processed_records),
                "execution_time": measure_execution_time(),
                "last_run": get_current_timestamp()
            }

        except Exception as e:
            log(f"Error in stage {stage.name}: {e}", level="error")
            total_errors = total_errors + 1

    # Load to destination
    if processed_records:
        try:
            load_to_destination(processed_records, pipeline.destination)
            log(f"Loaded {len(processed_records)} records to {pipeline.destination}")
        except Exception as e:
            log(f"Error loading to destination: {e}", level="error")
            total_errors = total_errors + 1

    # Update pipeline status
    pipeline.error_count = total_errors
    if total_errors == 0:
        pipeline.status = "completed"
    else:
        pipeline.status = "completed_with_errors"

    results = {
        "pipeline_id": pipeline.id,
        "total_processed": total_processed,
        "total_loaded": len(processed_records),
        "total_errors": total_errors,
        "execution_time": measure_total_execution_time(),
        "status": pipeline.status
    }

    log(f"Pipeline {pipeline.name} completed: {results}")
    return results

# Helper functions
def validate_type(value, expected_type: str) -> bool:
    if expected_type == "string":
        return isinstance(value, str)
    elif expected_type == "number":
        return isinstance(value, (int, float))
    elif expected_type == "boolean":
        return isinstance(value, bool)
    elif expected_type == "array":
        return isinstance(value, list)
    elif expected_type == "object":
        return isinstance(value, dict)
    return true

def normalize_phone_number(phone: str) -> str:
    # Simple phone normalization
    if not phone:
        return ""

    # Remove non-digits
    digits_only = "".join(c for c in phone if c.isdigit())

    # Format as (XXX) XXX-XXXX for US numbers
    if len(digits_only) == 10:
        return f"({digits_only[:3]}) {digits_only[3:6]}-{digits_only[6:]}"
    elif len(digits_only) == 11 and digits_only.startswith("1"):
        return f"({digits_only[1:4]}) {digits_only[4:7]}-{digits_only[7:]}"

    return phone  # Return original if can't normalize

# Usage example
def create_analytics_pipeline() -> Pipeline:
    # Define data sources
    customer_db = DataSource(
        id="SRC-001",
        name="Customer Database",
        type="database",
        connection_string="postgresql://user:pass@localhost/customers",
        format="sql",
        schema={
            "required": ["customer_id", "email", "created_at"],
            "types": {
                "customer_id": "string",
                "email": "string", 
                "created_at": "string",
                "age": "number"
            }
        },
        last_updated=""
    )

    sales_api = DataSource(
        id="SRC-002",
        name="Sales API",
        type="api",
        connection_string="https://api.company.com/sales",
        format="json",
        schema={
            "required": ["sale_id", "customer_id", "amount"],
            "types": {
                "sale_id": "string",
                "customer_id": "string",
                "amount": "number"
            }
        },
        last_updated=""
    )

    # Define processing stages
    transform_stage = ProcessingStage(
        name="transform",
        input_type="raw",
        output_type="normalized",
        configuration={
            "field_mappings": {
                "customer_id": "cust_id",
                "created_at": "registration_date"
            },
            "enrichment": {
                "email": "ai_classify_domain",
                "phone": "normalize_phone"
            }
        },
        metrics={}
    )

    filter_stage = ProcessingStage(
        name="filter",
        input_type="normalized",
        output_type="filtered",
        configuration={
            "quality_threshold": 80.0,
            "date_range": {
                "start": "2024-01-01",
                "end": "2024-12-31"
            }
        },
        metrics={}
    )

    # Create pipeline
    pipeline = Pipeline(
        id="PIPE-001",
        name="Customer Analytics Pipeline",
        sources=[customer_db, sales_api],
        stages=[transform_stage, filter_stage],
        destination="data_warehouse.analytics.customer_360",
        schedule="daily",
        status="stopped",
        last_run="",
        error_count=0
    )

    return pipeline

def run_analytics_pipeline():
    pipeline = create_analytics_pipeline()
    results = pipeline.execute_pipeline()

    # Generate summary report
    summary = reason(
        "Generate a summary report of the pipeline execution",
        context=results
    )

    log(f"Pipeline Summary: {summary}")
    return results

Configuration Management

Application Configuration System

struct DatabaseConfig:
    host: str
    port: int
    database: str
    username: str
    password: str
    ssl_enabled: bool
    connection_pool_size: int
    timeout_seconds: int

struct APIConfig:
    base_url: str
    api_key: str
    rate_limit_per_minute: int
    timeout_seconds: int
    retry_attempts: int
    enable_logging: bool

struct FeatureFlags:
    use_new_algorithm: bool
    enable_caching: bool
    debug_mode: bool
    beta_features: bool
    ai_suggestions: bool

struct AppConfig:
    environment: str  # "development", "staging", "production"
    debug: bool
    log_level: str
    database: DatabaseConfig
    api: APIConfig
    features: FeatureFlags
    version: str
    deployment_time: str

# Configuration management functions
def load_config_from_environment() -> AppConfig:
    # Load from environment variables
    env = get_environment()

    database_config = DatabaseConfig(
        host=env.get("DB_HOST", "localhost"),
        port=int(env.get("DB_PORT", "5432")),
        database=env.get("DB_NAME", "app_db"),
        username=env.get("DB_USER", "app_user"),
        password=env.get("DB_PASSWORD", ""),
        ssl_enabled=env.get("DB_SSL", "false").lower() == "true",
        connection_pool_size=int(env.get("DB_POOL_SIZE", "10")),
        timeout_seconds=int(env.get("DB_TIMEOUT", "30"))
    )

    api_config = APIConfig(
        base_url=env.get("API_BASE_URL", "https://api.example.com"),
        api_key=env.get("API_KEY", ""),
        rate_limit_per_minute=int(env.get("API_RATE_LIMIT", "100")),
        timeout_seconds=int(env.get("API_TIMEOUT", "30")),
        retry_attempts=int(env.get("API_RETRIES", "3")),
        enable_logging=env.get("API_LOGGING", "true").lower() == "true"
    )

    feature_flags = FeatureFlags(
        use_new_algorithm=env.get("FEATURE_NEW_ALGO", "false").lower() == "true",
        enable_caching=env.get("FEATURE_CACHE", "true").lower() == "true",
        debug_mode=env.get("FEATURE_DEBUG", "false").lower() == "true",
        beta_features=env.get("FEATURE_BETA", "false").lower() == "true",
        ai_suggestions=env.get("FEATURE_AI", "true").lower() == "true"
    )

    config = AppConfig(
        environment=env.get("ENVIRONMENT", "development"),
        debug=env.get("DEBUG", "false").lower() == "true",
        log_level=env.get("LOG_LEVEL", "INFO"),
        database=database_config,
        api=api_config,
        features=feature_flags,
        version=env.get("APP_VERSION", "1.0.0"),
        deployment_time=get_current_timestamp()
    )

    return config

def validate_config(config: AppConfig) -> dict:
    validation_results = {
        "valid": true,
        "errors": [],
        "warnings": []
    }

    # Database validation
    if not config.database.host:
        validation_results["errors"].append("Database host is required")
        validation_results["valid"] = false

    if config.database.port < 1 or config.database.port > 65535:
        validation_results["errors"].append("Database port must be between 1 and 65535")
        validation_results["valid"] = false

    if not config.database.password and config.environment == "production":
        validation_results["errors"].append("Database password is required in production")
        validation_results["valid"] = false

    # API validation
    if not config.api.api_key and config.environment == "production":
        validation_results["errors"].append("API key is required in production")
        validation_results["valid"] = false

    if not config.api.base_url.startswith("https") and config.environment == "production":
        validation_results["warnings"].append("HTTPS is recommended for production API endpoints")

    # Environment-specific validation
    if config.environment == "production":
        if config.debug:
            validation_results["warnings"].append("Debug mode should be disabled in production")

        if config.features.debug_mode:
            validation_results["warnings"].append("Debug features should be disabled in production")

    # Performance validation
    if config.database.connection_pool_size > 50:
        validation_results["warnings"].append("Large connection pools may impact performance")

    if config.api.rate_limit_per_minute < 10:
        validation_results["warnings"].append("Very low rate limits may cause application issues")

    # AI-powered validation
    ai_validation = reason(
        "Review this configuration for potential security or performance issues",
        context=config,
        temperature=0.1
    )

    if "issue" in ai_validation.lower() or "warning" in ai_validation.lower():
        validation_results["warnings"].append(f"AI analysis: {ai_validation}")

    return validation_results

def apply_environment_overrides(config: AppConfig, environment: str) -> AppConfig:
    # Apply environment-specific overrides
    if environment == "production":
        config.debug = false
        config.features.debug_mode = false
        config.log_level = "WARN"
        config.database.ssl_enabled = true

    elif environment == "staging":
        config.debug = false
        config.features.beta_features = true
        config.log_level = "INFO"

    elif environment == "development":
        config.debug = true
        config.features.debug_mode = true
        config.features.beta_features = true
        config.log_level = "DEBUG"

    return config

def generate_config_documentation(config: AppConfig) -> str:
    # AI-generated configuration documentation
    documentation = reason(
        "Generate comprehensive documentation for this application configuration",
        context=config
    )

    return documentation

def monitor_config_changes(old_config: AppConfig, new_config: AppConfig) -> dict:
    changes = {
        "changed_fields": [],
        "security_impact": false,
        "performance_impact": false,
        "restart_required": false
    }

    # Database changes
    if old_config.database.host != new_config.database.host:
        changes["changed_fields"].append("database.host")
        changes["restart_required"] = true

    if old_config.database.connection_pool_size != new_config.database.connection_pool_size:
        changes["changed_fields"].append("database.connection_pool_size")
        changes["performance_impact"] = true

    # Security-sensitive changes
    if old_config.database.ssl_enabled != new_config.database.ssl_enabled:
        changes["changed_fields"].append("database.ssl_enabled")
        changes["security_impact"] = true

    if old_config.api.api_key != new_config.api.api_key:
        changes["changed_fields"].append("api.api_key")
        changes["security_impact"] = true

    # Feature flag changes
    if old_config.features.use_new_algorithm != new_config.features.use_new_algorithm:
        changes["changed_fields"].append("features.use_new_algorithm")
        changes["performance_impact"] = true

    # AI analysis of changes
    if changes["changed_fields"]:
        impact_analysis = reason(
            "Analyze the impact of these configuration changes",
            context=changes["changed_fields"]
        )
        changes["impact_analysis"] = impact_analysis

    return changes

# Usage patterns
def config_management_workflow():
    # Load configuration
    config = load_config_from_environment()
    log(f"Loaded configuration for {config.environment} environment")

    # Validate configuration
    validation = config.validate_config()
    if not validation["valid"]:
        log("Configuration validation failed:", level="error")
        for error in validation["errors"]:
            log(f"  Error: {error}", level="error")
        return false

    if validation["warnings"]:
        log("Configuration warnings:")
        for warning in validation["warnings"]:
            log(f"  Warning: {warning}", level="warn")

    # Apply environment-specific settings
    config = config.apply_environment_overrides(config.environment)

    # Generate documentation
    docs = config.generate_config_documentation()
    save_documentation("config_docs.md", docs)

    # Set up monitoring for future changes
    save_config_snapshot(config)

    log("Configuration management completed successfully")
    return config

def hot_reload_config(current_config: AppConfig) -> AppConfig:
    # Load new configuration
    new_config = load_config_from_environment()

    # Validate new configuration
    validation = new_config.validate_config()
    if not validation["valid"]:
        log("New configuration is invalid, keeping current config", level="error")
        return current_config

    # Analyze changes
    changes = monitor_config_changes(current_config, new_config)

    if changes["restart_required"]:
        log("Configuration changes require application restart", level="warn")
        schedule_restart()

    if changes["security_impact"]:
        log("Configuration changes have security implications", level="warn")
        notify_security_team(changes)

    log(f"Configuration reloaded with {len(changes['changed_fields'])} changes")
    return new_config

Summary

These patterns demonstrate Dana's strengths in building maintainable, AI-integrated business applications:

  1. Clear Domain Modeling: Structs represent business concepts naturally
  2. Flexible Function Dispatch: Same function names work with different types
  3. AI Integration: Natural reasoning capabilities for complex business logic
  4. Type Safety: Type hints guide both humans and AI
  5. Composability: Small, focused functions combine into powerful workflows

Key principles from these patterns:

  • Separate Data from Behavior: Structs hold state, functions provide operations
  • Leverage AI Reasoning: Use reason() for complex analysis and decision-making
  • Design for Maintainability: Clear naming and type hints make code self-documenting
  • Handle Errors Gracefully: Validate inputs and provide meaningful error messages
  • Performance Awareness: Understand overhead and optimize hot paths when needed

[{"id": "phase6_user_documentation", "content": "Create comprehensive user-focused struct documentation", "status": "completed", "priority": "high"}, {"id": "phase6_dana_vs_languages", "content": "Document Dana vs Python/Go comparisons", "status": "completed", "priority": "high"}, {"id": "phase6_best_practices", "content": "Create best practices guide for Dana functions and structs", "status": "completed", "priority": "high"}, {"id": "phase6_examples_library", "content": "Build comprehensive examples library", "status": "completed", "priority": "medium"}, {"id": "phase6_consistency_review", "content": "Review docs for consistency and eliminate contradictions", "status": "in_progress", "priority": "medium"}]