Extended Functionality

def walk(path, symlinks=True, keep_file=ret_true, keep_folder=ret_true, skip_folder=ret_false, func=os.path.join, ret_folders=False):
    """
    Generator version of os.walk with functional filtering.
    
    Enhanced directory traversal with customizable file and folder filtering
    using predicate functions. Provides more control than standard os.walk.
    
    Parameters:
    - path: Path|str, starting directory path
    - symlinks: bool, follow symbolic links (default: True)
    - keep_file: callable, function returning True for wanted files (default: ret_true)
    - keep_folder: callable, function returning True for folders to enter (default: ret_true)
    - skip_folder: callable, function returning True for folders to skip (default: ret_false)
    - func: callable, function to apply to each matched file (default: os.path.join)
    - ret_folders: bool, yield folders in addition to files (default: False)
    
    Yields:
    Results of func(root, name) for each matching file/folder
    """

def globtastic(path, recursive=True, symlinks=True, file_glob=None, file_re=None, 
               folder_re=None, skip_file_glob=None, skip_file_re=None, 
               skip_folder_re=None, func=os.path.join, ret_folders=False):
    """
    Enhanced glob with regex matches, symlink handling, and skip parameters.
    
    More powerful alternative to glob.glob with support for regex patterns,
    exclusion rules, and advanced filtering options.
    
    Parameters:
    - path: Path|str, starting directory path
    - recursive: bool, search subdirectories (default: True)
    - symlinks: bool, follow symbolic links (default: True)
    - file_glob: str, glob pattern for file inclusion
    - file_re: str, regex pattern for file inclusion
    - folder_re: str, regex pattern for folder inclusion
    - skip_file_glob: str, glob pattern for file exclusion
    - skip_file_re: str, regex pattern for file exclusion
    - skip_folder_re: str, regex pattern for folder exclusion
    - func: callable, function to apply to matches
    - ret_folders: bool, include folders in results
    
    Returns:
    L: List of paths matching the criteria
    """

def mkdir(path, exist_ok=False, parents=False, overwrite=False, **kwargs):
    """
    Create directory with enhanced options.
    
    Creates directory with Path support and optional overwrite capability.
    More flexible than standard os.makedirs.
    
    Parameters:
    - path: Path|str, directory to create
    - exist_ok: bool, don't raise error if directory exists
    - parents: bool, create parent directories as needed
    - overwrite: bool, remove existing directory first
    - **kwargs: additional arguments passed to Path.mkdir
    
    Returns:
    Path: The created directory path
    """

@contextmanager
def maybe_open(f, mode='r', **kwargs):
    """
    Context manager: open file if path, otherwise return as-is.
    
    Flexible file handling that works with both file paths and file objects.
    Automatically handles opening and closing for paths while passing through
    already opened file objects.
    
    Parameters:
    - f: str|PathLike|file-like, file path or file object
    - mode: str, file opening mode (default: 'r')
    - **kwargs: additional arguments for open()
    
    Yields:
    File object ready for reading/writing
    """

def loads(s, **kwargs):
    """
    Load JSON with enhanced error handling.
    
    JSON loading with better error messages and support for Path objects.
    Handles common JSON parsing errors gracefully.
    
    Parameters:
    - s: str|Path, JSON string or file path
    - **kwargs: additional arguments for json.loads
    
    Returns:
    Parsed JSON object
    
    Raises:
    Informative errors for malformed JSON
    """

def loads_multi(s, **kwargs):
    """
    Load multiple JSON objects from string or file.
    
    Handles JSONL (JSON Lines) format and multiple JSON objects
    separated by whitespace.
    
    Parameters:
    - s: str|Path, JSON string or file path containing multiple objects
    - **kwargs: additional arguments for json.loads
    
    Returns:
    List of parsed JSON objects
    """

def dumps(obj, **kwargs):
    """
    Dump object to JSON with Path handling.
    
    Enhanced JSON serialization with support for Path objects
    and sensible defaults for common use cases.
    
    Parameters:
    - obj: Object to serialize
    - **kwargs: additional arguments for json.dumps
    
    Returns:
    str: JSON string representation
    """

def save_pickle(fn, o):
    """
    Save object to pickle file.
    
    Parameters:
    - fn: Path|str, file path for pickle
    - o: Object to pickle
    """

def load_pickle(fn):
    """
    Load object from pickle file.
    
    Parameters:
    - fn: Path|str, pickle file path
    
    Returns:
    Unpickled object
    """

def bunzip(fn):
    """
    Decompress bzip2 data from file or bytes.
    
    Parameters:
    - fn: Path|str|bytes, bzip2 compressed data or file path
    
    Returns:
    bytes: Decompressed data
    """

def run(cmd, *rest, same_in_win=False, ignore_ex=False, as_bytes=False, stderr=False):
    """
    Run system command with enhanced error handling.
    
    Execute shell commands with flexible argument handling and
    comprehensive error reporting. Supports both string and list
    command specifications.
    
    Parameters:
    - cmd: str|list, command to execute
    - *rest: additional command arguments
    - same_in_win: bool, don't modify command for Windows compatibility
    - ignore_ex: bool, return None instead of raising on errors
    - as_bytes: bool, return output as bytes instead of string
    - stderr: bool, include stderr in output
    
    Returns:
    str|bytes|None: Command output or None if error and ignore_ex=True
    
    Raises:
    RuntimeError: If command fails and ignore_ex=False
    """

def exec_eval(code, glob=None, loc=None):
    """
    Execute code and return result of last expression.
    
    Enhanced exec that can return the value of the last expression
    in the code block, combining exec and eval functionality.
    
    Parameters:
    - code: str, Python code to execute
    - glob: dict, global namespace (default: None)
    - loc: dict, local namespace (default: None)
    
    Returns:
    Result of last expression in code, or None if no expression
    """

@contextmanager
def modified_env(**kwargs):
    """
    Context manager to temporarily modify environment variables.
    
    Parameters:
    - **kwargs: environment variables to set
    
    Usage:
    with modified_env(PATH="/new/path", DEBUG="1"):
        # Environment modified here
        subprocess.run(...)
    # Environment restored here
    """

def set_num_threads(n):
    """
    Set number of threads for various libraries.
    
    Sets thread counts for NumPy, OpenMP, and other numerical libraries
    to optimize performance on multi-core systems.
    
    Parameters:
    - n: int, number of threads to use
    """

def flexicache(cache_dir=None, **kwargs):
    """
    Flexible caching decorator with multiple policies.
    
    Advanced caching with support for different cache policies including
    time-based expiration and modification time checking.
    
    Parameters:
    - cache_dir: Path|str, directory for cache files
    - **kwargs: additional caching options
    
    Returns:
    Decorator function for caching
    """

def time_policy(seconds):
    """
    Cache policy based on time expiration.
    
    Parameters:
    - seconds: int|float, cache duration in seconds
    
    Returns:
    Policy function for time-based cache expiration
    """

def mtime_policy():
    """
    Cache policy based on file modification time.
    
    Invalidates cache when source files are modified.
    
    Returns:
    Policy function for mtime-based cache invalidation
    """

def timed_cache(seconds=3600):
    """
    Simple time-based cache decorator.
    
    Parameters:
    - seconds: int, cache duration (default: 3600)
    
    Returns:
    Caching decorator
    """

class CachedIter:
    """
    Iterator that caches results for repeated iteration.
    
    Allows multiple iterations over the same data without
    recomputing expensive operations.
    
    Parameters:
    - func: callable, function that returns an iterator
    - *args: arguments for func
    - **kwargs: keyword arguments for func
    """
    
    def __init__(self, func, *args, **kwargs): ...
    def __iter__(self): ...

class CachedAwaitable:
    """
    Cache results of async operations.
    
    Provides caching for coroutines and async functions to avoid
    redundant async operations.
    
    Parameters:
    - coro: coroutine to cache
    """
    
    def __init__(self, coro): ...
    def __await__(self): ...

def reawaitable(f):
    """
    Decorator to make async functions re-awaitable.
    
    Allows the same coroutine result to be awaited multiple times
    without re-execution.
    
    Parameters:
    - f: async function to make re-awaitable
    
    Returns:
    Decorated async function
    """

class IterLen:
    """
    Iterator wrapper that supports len().
    
    Wraps iterators to provide length information when the
    underlying iterable has a __len__ method.
    
    Parameters:
    - items: iterable to wrap
    """
    
    def __init__(self, items): ...
    def __iter__(self): ...
    def __len__(self): ...

class ReindexCollection:
    """
    Collection that supports reindexing operations.
    
    Provides advanced indexing capabilities with support for
    reordering and subset selection.
    
    Parameters:
    - items: initial collection items
    """
    
    def __init__(self, items): ...
    def reindex(self, idxs): ...
    def __getitem__(self, idx): ...

class SaveReturn:
    """
    Context manager to save and return iteration results.
    
    Captures all yielded values from an iterator for later access
    while still allowing normal iteration.
    
    Parameters:
    - it: iterator to wrap
    """
    
    def __init__(self, it): ...
    def __enter__(self): ...
    def __exit__(self, *args): ...
    def __iter__(self): ...

def dict2obj(d, **kwargs):
    """
    Convert dictionary to object with attribute access.
    
    Parameters:
    - d: dict, dictionary to convert
    - **kwargs: additional attributes to set
    
    Returns:
    Object with dictionary keys as attributes
    """

def obj2dict(obj, **kwargs):
    """
    Convert object to dictionary.
    
    Parameters:
    - obj: object to convert
    - **kwargs: additional dictionary entries
    
    Returns:
    dict: Object attributes as dictionary
    """

def is_listy(x):
    """
    Check if object is list-like but not string/dict.
    
    Parameters:
    - x: object to check
    
    Returns:
    bool: True if list-like (iterable but not string/dict)
    """

def mapped(f):
    """
    Create a mapped version of an iterable.
    
    Parameters:
    - f: function to map over items
    
    Returns:
    Function that applies f to iterables
    """

def truncstr(s, maxlen=50, suf='…'):
    """
    Truncate string with suffix if too long.
    
    Parameters:
    - s: str, string to truncate
    - maxlen: int, maximum length (default: 50)
    - suf: str, suffix for truncated strings (default: '…')
    
    Returns:
    str: Truncated string with suffix if needed
    """

def sparkline(data, mn=None, mx=None):
    """
    Create Unicode sparkline from numeric data.
    
    Parameters:
    - data: iterable of numbers
    - mn: float, minimum value (auto-detected if None)
    - mx: float, maximum value (auto-detected if None)
    
    Returns:
    str: Unicode sparkline representation
    """

class PartialFormatter(string.Formatter):
    """
    String formatter that handles missing keys gracefully.
    
    Allows partial string formatting where some placeholders
    can remain unfilled without raising KeyError.
    """
    
    def get_value(self, key, args, kwargs): ...

def partial_format(s, **kwargs):
    """
    Partially format string, leaving unfilled placeholders.
    
    Parameters:
    - s: str, format string with placeholders
    - **kwargs: values for available placeholders
    
    Returns:
    str: Partially formatted string
    """

def stringfmt_names(s):
    """
    Extract placeholder names from format string.
    
    Parameters:
    - s: str, format string
    
    Returns:
    set: Set of placeholder names
    """

class EventTimer:
    """
    Timer for measuring event durations with context manager support.
    
    Provides precise timing measurements with automatic formatting
    and optional storage of timing results.
    
    Parameters:
    - store: bool, store timing results (default: False)
    - run: bool, start timing immediately (default: True)
    """
    
    def __init__(self, store=False, run=True): ...
    def __enter__(self): ...
    def __exit__(self, *args): ...
    def start(self): ...
    def stop(self): ...

def trace(f):
    """
    Decorator to trace function calls with arguments and results.
    
    Prints function name, arguments, and return values for debugging.
    Useful for understanding program flow and data transformations.
    
    Parameters:
    - f: function to trace
    
    Returns:
    Wrapped function with tracing
    """

def modify_exception(e, msg_func, **kwargs):
    """
    Modify exception message with additional context.
    
    Parameters:
    - e: Exception to modify
    - msg_func: function to transform exception message
    - **kwargs: additional context for message
    
    Returns:
    Modified exception
    """

def round_multiple(x, mult=1):
    """
    Round number to nearest multiple.
    
    Parameters:
    - x: number to round
    - mult: multiple to round to (default: 1)
    
    Returns:
    Number rounded to nearest multiple
    """

class ContextManagers:
    """
    Manage multiple context managers as a single unit.
    
    Allows entering and exiting multiple context managers together,
    with proper cleanup even if some fail.
    
    Parameters:
    - *cms: context managers to manage
    """
    
    def __init__(self, *cms): ...
    def __enter__(self): ...
    def __exit__(self, *args): ...

from fastcore.xtras import walk, globtastic, mkdir

# Advanced directory walking with filtering
python_files = list(walk(
    "src", 
    keep_file=lambda root, name: name.endswith('.py'),
    skip_folder=lambda root, name: name.startswith('.')
))

# Powerful glob with regex and exclusions
source_files = globtastic(
    "project",
    file_re=r".*\.(py|js|ts)$",
    skip_folder_re=r"(node_modules|__pycache__|\.git)",
    recursive=True
)

# Create directory with overwrite
build_dir = mkdir("build", parents=True, overwrite=True)

from fastcore.xtras import flexicache, timed_cache, CachedIter

# Flexible caching with time policy
@flexicache(cache_dir=".cache")
def expensive_computation(data):
    # Time-intensive processing
    return process_data(data)

# Simple time-based caching
@timed_cache(seconds=300)  # 5 minute cache
def api_call(endpoint):
    return requests.get(endpoint).json()

# Cache iterator results
def data_generator():
    for i in range(1000000):
        yield expensive_transform(i)

cached_data = CachedIter(data_generator)
# First iteration computes and caches
for item in cached_data: process(item)
# Second iteration uses cached results
for item in cached_data: analyze(item)

from fastcore.xtras import run, modified_env, exec_eval

# Enhanced command execution
result = run(["python", "script.py", "--flag"], 
             stderr=True, ignore_ex=True)

# Temporary environment modification
with modified_env(DEBUG="1", LOG_LEVEL="verbose"):
    run("my_app --config dev.json")

# Execute code and get result
result = exec_eval("""
x = 10
y = 20
x + y  # This value is returned
""")
print(result)  # 30

from fastcore.xtras import dict2obj, ReindexCollection, SaveReturn

# Dictionary to object conversion
config = dict2obj({
    "model": "resnet50", 
    "lr": 0.01,
    "batch_size": 32
})
print(config.model)  # "resnet50"

# Reindexing collections
data = ReindexCollection([10, 20, 30, 40, 50])
subset = data.reindex([0, 2, 4])  # [10, 30, 50]

# Save iteration results
def number_generator():
    for i in range(5):
        yield i * i

with SaveReturn(number_generator()) as saver:
    for val in saver:
        print(f"Processing {val}")

results = saver.values  # [0, 1, 4, 9, 16]

from fastcore.xtras import truncstr, sparkline, partial_format

# String truncation
long_text = "This is a very long string that needs truncation"
short = truncstr(long_text, maxlen=20)  # "This is a very lo…"

# Unicode sparklines
data = [1, 3, 7, 4, 2, 8, 5, 3, 2, 1]
chart = sparkline(data)  # "▁▃▇▄▂█▅▃▂▁"

# Partial string formatting
template = "Hello {name}, your score is {score}"
partial = partial_format(template, name="Alice")
# "Hello Alice, your score is {score}"

from fastcore.xtras import EventTimer, trace, ContextManagers

# Precise timing
with EventTimer() as timer:
    expensive_operation()
print(f"Operation took {timer.elapsed:.3f} seconds")

# Function tracing
@trace
def fibonacci(n):
    if n <= 1: return n
    return fibonacci(n-1) + fibonacci(n-2)

# Managing multiple contexts
from contextlib import contextmanager

@contextmanager
def temp_file(): 
    # ... create temp file
    yield file
    # ... cleanup

with ContextManagers(open('file1.txt'), temp_file(), timer):
    # All contexts entered together
    process_files()
# All contexts properly exited