Dialects and Configuration

class SimpleDialect:
    """
    Simplified dialect object for CSV parsing configuration.
    
    For delimiter, quotechar, and escapechar:
    - Empty string ('') means no delimiter/quotechar/escapechar in the file
    - None is used to mark it as undefined
    """
    
    def __init__(
        self,
        delimiter: Optional[str],
        quotechar: Optional[str],
        escapechar: Optional[str],
        strict: bool = False
    ):
        """
        Create a new SimpleDialect.
        
        Parameters:
        - delimiter: Field delimiter character
        - quotechar: Quote character for fields containing special characters
        - escapechar: Escape character for escaping delimiters/quotes
        - strict: Whether to enforce strict parsing
        """
    
    def validate(self) -> None:
        """
        Validate dialect parameters.
        
        Raises:
        ValueError: If any parameter is invalid
        """
    
    def to_csv_dialect(self) -> csv.Dialect:
        """
        Convert to standard csv.Dialect object.
        
        Returns:
        csv.Dialect compatible object
        """
    
    def to_dict(self) -> Dict[str, Union[str, bool, None]]:
        """
        Convert dialect to dictionary representation.
        
        Returns:
        Dictionary with dialect parameters
        """
    
    def serialize(self) -> str:
        """
        Serialize dialect to JSON string.
        
        Returns:
        JSON string representation of dialect
        """
    
    @classmethod
    def deserialize(cls, obj: str) -> 'SimpleDialect':
        """
        Deserialize dialect from JSON string.
        
        Parameters:
        - obj: JSON string representation
        
        Returns:
        SimpleDialect instance
        """
    
    @classmethod
    def from_dict(cls, d: Dict[str, Any]) -> 'SimpleDialect':
        """
        Create SimpleDialect from dictionary.
        
        Parameters:
        - d: Dictionary with dialect parameters
        
        Returns:
        SimpleDialect instance
        """
    
    @classmethod
    def from_csv_dialect(cls, d: csv.Dialect) -> 'SimpleDialect':
        """
        Create SimpleDialect from csv.Dialect.
        
        Parameters:
        - d: csv.Dialect instance
        
        Returns:
        SimpleDialect instance
        """

import clevercsv
import json

# Create custom dialect
dialect = clevercsv.SimpleDialect(',', '"', '\\', strict=True)
print(f"Delimiter: '{dialect.delimiter}'")
print(f"Quote char: '{dialect.quotechar}'")
print(f"Escape char: '{dialect.escapechar}'")

# Validate dialect
try:
    dialect.validate()
    print("Dialect is valid")
except ValueError as e:
    print(f"Invalid dialect: {e}")

# Convert to csv.Dialect for use with standard library
csv_dialect = dialect.to_csv_dialect()
with open('data.csv', 'r', newline='') as f:
    reader = csv.reader(f, dialect=csv_dialect)
    data = list(reader)

# Serialize dialect for storage
serialized = dialect.serialize()
print(f"Serialized: {serialized}")

# Deserialize dialect
restored_dialect = clevercsv.SimpleDialect.deserialize(serialized)
print(f"Restored: {restored_dialect}")

# Create from dictionary
dialect_dict = {'delimiter': ';', 'quotechar': "'", 'escapechar': '', 'strict': False}
dialect_from_dict = clevercsv.SimpleDialect.from_dict(dialect_dict)

# Create from csv.Dialect
csv_excel = csv.excel
simple_from_csv = clevercsv.SimpleDialect.from_csv_dialect(csv_excel)

# Standard CSV dialects
excel: csv.Dialect          # Excel-compatible format (comma-separated, quoted fields)
excel_tab: csv.Dialect      # Excel tab-separated format
unix_dialect: csv.Dialect   # Unix-style format (comma-separated, quoted fields, escaped quotes)

import clevercsv

# Use predefined dialects
with open('data.csv', 'r', newline='') as f:
    reader = clevercsv.reader(f, dialect=clevercsv.excel)
    data = list(reader)

# Compare dialects
print("Excel dialect:")
excel_simple = clevercsv.SimpleDialect.from_csv_dialect(clevercsv.excel)
print(f"  Delimiter: '{excel_simple.delimiter}'")
print(f"  Quote char: '{excel_simple.quotechar}'")

print("Unix dialect:")
unix_simple = clevercsv.SimpleDialect.from_csv_dialect(clevercsv.unix_dialect)
print(f"  Delimiter: '{unix_simple.delimiter}'")
print(f"  Quote char: '{unix_simple.quotechar}'")
print(f"  Escape char: '{unix_simple.escapechar}'")

def field_size_limit(*args, **kwargs) -> int:
    """
    Get or set the field size limit for CSV parsing.
    
    Parameters:
    - limit (optional): New field size limit in characters
    
    Returns:
    Previous field size limit
    
    Raises:
    TypeError: If limit is not an integer or too many arguments provided
    
    Notes:
    - Default limit is 128KB (131,072 characters)
    - Setting limit to 0 removes the limit (use with caution)
    - Large limits may impact performance and memory usage
    """

import clevercsv

# Get current field size limit
current_limit = clevercsv.field_size_limit()
print(f"Current field size limit: {current_limit} characters")

# Set new field size limit
old_limit = clevercsv.field_size_limit(256 * 1024)  # 256KB
print(f"Previous limit: {old_limit}, New limit: {clevercsv.field_size_limit()}")

# Remove field size limit (use with caution)
clevercsv.field_size_limit(0)
print("Field size limit removed")

# Restore reasonable limit
clevercsv.field_size_limit(128 * 1024)  # 128KB default

import clevercsv

def create_pipe_separated_dialect():
    """Create dialect for pipe-separated values."""
    return clevercsv.SimpleDialect('|', '"', '\\')

def create_tab_separated_no_quotes():
    """Create dialect for tab-separated without quotes."""
    return clevercsv.SimpleDialect('\t', '', '')

def create_semicolon_single_quotes():
    """Create dialect for semicolon-separated with single quotes."""
    return clevercsv.SimpleDialect(';', "'", '')

# Usage
pipe_dialect = create_pipe_separated_dialect()
with open('pipe_data.csv', 'r', newline='') as f:
    reader = clevercsv.reader(f, dialect=pipe_dialect)
    data = list(reader)

import clevercsv

def compare_dialects(file_path, dialects):
    """Compare how different dialects parse the same file."""
    
    results = {}
    
    with open(file_path, 'r', newline='') as f:
        sample = f.read(1000)  # First 1000 characters
    
    for name, dialect in dialects.items():
        try:
            # Parse sample with this dialect
            rows = list(clevercsv.parse_string(sample, dialect))
            results[name] = {
                'rows': len(rows),
                'columns': len(rows[0]) if rows else 0,
                'sample_row': rows[0] if rows else []
            }
        except Exception as e:
            results[name] = {'error': str(e)}
    
    return results

# Usage
dialects = {
    'comma': clevercsv.SimpleDialect(',', '"', ''),
    'semicolon': clevercsv.SimpleDialect(';', '"', ''),
    'pipe': clevercsv.SimpleDialect('|', '"', ''),
    'tab': clevercsv.SimpleDialect('\t', '"', '')
}

comparison = compare_dialects('ambiguous.csv', dialects)
for name, result in comparison.items():
    print(f"{name}: {result}")

import clevercsv
import json

class DialectManager:
    """Manage dialect configurations with persistence."""
    
    def __init__(self, config_file='dialects.json'):
        self.config_file = config_file
        self.dialects = {}
        self.load_dialects()
    
    def save_dialect(self, name, dialect):
        """Save a dialect configuration."""
        self.dialects[name] = dialect.to_dict()
        self._save_to_file()
    
    def load_dialect(self, name):
        """Load a dialect configuration."""
        if name in self.dialects:
            return clevercsv.SimpleDialect.from_dict(self.dialects[name])
        return None
    
    def list_dialects(self):
        """List all saved dialects."""
        return list(self.dialects.keys())
    
    def delete_dialect(self, name):
        """Delete a dialect configuration."""
        if name in self.dialects:
            del self.dialects[name]
            self._save_to_file()
    
    def load_dialects(self):
        """Load dialects from file."""
        try:
            with open(self.config_file, 'r') as f:
                self.dialects = json.load(f)
        except FileNotFoundError:
            self.dialects = {}
    
    def _save_to_file(self):
        """Save dialects to file."""
        with open(self.config_file, 'w') as f:
            json.dump(self.dialects, f, indent=2)

# Usage
manager = DialectManager()

# Save custom dialects
custom_dialect = clevercsv.SimpleDialect('|', "'", '\\')
manager.save_dialect('pipe_single_quote', custom_dialect)

# Load and use saved dialect
loaded_dialect = manager.load_dialect('pipe_single_quote')
if loaded_dialect:
    with open('data.csv', 'r', newline='') as f:
        reader = clevercsv.reader(f, dialect=loaded_dialect)
        data = list(reader)

import clevercsv

def smart_csv_processing(file_path):
    """Process CSV with detection fallback to configuration."""
    
    # Try automatic detection first
    detected_dialect = clevercsv.detect_dialect(file_path)
    
    if detected_dialect:
        print(f"Using detected dialect: {detected_dialect}")
        dialect = detected_dialect
    else:
        # Fallback to common dialects
        print("Detection failed, trying common dialects...")
        
        common_dialects = [
            clevercsv.SimpleDialect(',', '"', ''),     # Standard CSV
            clevercsv.SimpleDialect(';', '"', ''),     # European CSV
            clevercsv.SimpleDialect('\t', '"', ''),    # Tab-separated
            clevercsv.SimpleDialect('|', '"', ''),     # Pipe-separated
        ]
        
        dialect = None
        for test_dialect in common_dialects:
            try:
                with open(file_path, 'r', newline='') as f:
                    reader = clevercsv.reader(f, dialect=test_dialect)
                    first_row = next(reader)
                    if len(first_row) > 1:  # Reasonable number of columns
                        dialect = test_dialect
                        print(f"Using fallback dialect: {dialect}")
                        break
            except:
                continue
        
        if not dialect:
            raise ValueError("Could not determine appropriate dialect")
    
    # Process file with determined dialect
    with open(file_path, 'r', newline='') as f:
        reader = clevercsv.reader(f, dialect=dialect)
        return list(reader)

# Usage
try:
    data = smart_csv_processing('difficult_file.csv')
    print(f"Successfully processed {len(data)} rows")
except ValueError as e:
    print(f"Processing failed: {e}")

import clevercsv

def validate_dialect_for_file(file_path, dialect):
    """Validate that a dialect works correctly for a file."""
    
    validation_results = {
        'valid': True,
        'issues': [],
        'statistics': {}
    }
    
    try:
        with open(file_path, 'r', newline='') as f:
            reader = clevercsv.reader(f, dialect=dialect)
            rows = list(reader)
        
        if not rows:
            validation_results['valid'] = False
            validation_results['issues'].append('No rows parsed')
            return validation_results
        
        # Check for consistent column count
        column_counts = [len(row) for row in rows]
        unique_counts = set(column_counts)
        
        if len(unique_counts) > 1:
            validation_results['issues'].append(
                f'Inconsistent column counts: {sorted(unique_counts)}'
            )
        
        # Gather statistics
        validation_results['statistics'] = {
            'total_rows': len(rows),
            'column_counts': dict(zip(*zip(*[(c, column_counts.count(c)) for c in unique_counts]))),
            'average_columns': sum(column_counts) / len(column_counts),
            'max_field_length': max(len(field) for row in rows for field in row) if rows else 0
        }
        
    except Exception as e:
        validation_results['valid'] = False
        validation_results['issues'].append(f'Parsing error: {str(e)}')
    
    return validation_results

# Usage
test_dialect = clevercsv.SimpleDialect(',', '"', '')
results = validate_dialect_for_file('test.csv', test_dialect)

if results['valid']:
    print("Dialect validation passed")
    print(f"Statistics: {results['statistics']}")
else:
    print("Dialect validation failed")
    print(f"Issues: {results['issues']}")