Supported Standard Library Modules

Shed Skin supports approximately 30 standard library modules, either fully or partially. This page provides a comprehensive overview of each supported module, organized by category.

Data Structures

array

Provides space-efficient arrays of numeric values. Support Level: Full support Example:

import array

# Create array of integers
arr = array.array('i', [1, 2, 3, 4, 5])
arr.append(6)
print(arr[0])  # 1

collections

Provides specialized container datatypes. Support Level: Partial (defaultdict, deque only) Supported:

defaultdict - Dictionary with default factory function
deque - Double-ended queue with fast appends/pops

Not Supported: namedtuple, Counter, OrderedDict, ChainMap Example:

from collections import defaultdict, deque

# defaultdict usage
d = defaultdict(int)
d['count'] += 1

# deque usage
dq = deque([1, 2, 3])
dq.append(4)
dq.appendleft(0)

heapq

Heap queue algorithm (priority queue). Support Level: Full support Example:

import heapq

heap = []
heapq.heappush(heap, 3)
heapq.heappush(heap, 1)
heapq.heappush(heap, 2)
print(heapq.heappop(heap))  # 1

bisect

Array bisection algorithms for maintaining sorted lists. Support Level: Full support Example:

import bisect

sorted_list = [1, 3, 5, 7]
bisect.insort(sorted_list, 4)
print(sorted_list)  # [1, 3, 4, 5, 7]

Text Processing

re

Regular expression operations using PCRE syntax. Support Level: Full support (PCRE-compatible) Example:

import re

pattern = re.compile(r'\d+')
match = pattern.search('The answer is 42')
if match:
    print(match.group())  # '42'

Note: Uses PCRE2 library, which may have slight syntax differences from Python’s re module.

string

Common string operations and constants. Support Level: Partial Supported: String constants (ascii_letters, digits, etc.) Not Supported: Format, Template classes Example:

import string

print(string.ascii_lowercase)  # 'abcdefghijklmnopqrstuvwxyz'
print(string.digits)  # '0123456789'

fnmatch

Unix filename pattern matching. Support Level: Full support Example:

import fnmatch

if fnmatch.fnmatch('test.py', '*.py'):
    print('Python file!')

File and Data Processing

csv

CSV file reading and writing. Support Level: Partial (ASCII-only) Supported:

reader - Read CSV files
writer - Write CSV files
DictReader - Read CSV as dictionaries
DictWriter - Write dictionaries as CSV

Not Supported: Sniffer class Limitations: ASCII characters only, no full Unicode support Example:

import csv

with open('data.csv', 'w') as f:
    writer = csv.writer(f)
    writer.writerow(['name', 'age'])
    writer.writerow(['Alice', '30'])

configparser

Configuration file parser. Support Level: Partial Supported: ConfigParser class Not Supported: SafeConfigParser (deprecated in Python 3) Example:

import configparser

config = configparser.ConfigParser()
config.read('config.ini')
value = config.get('section', 'key')

struct

Interpret bytes as packed binary data. Support Level: Partial Supported: pack, unpack, calcsize functions Not Supported: Struct class, iter_unpack Example:

import struct

data = struct.pack('i', 42)
value = struct.unpack('i', data)[0]

base64

Base64 encoding and decoding. Support Level: Partial Supported: Standard base64 encoding/decoding Not Supported: base16, base32, base85 variants Example:

import base64

encoded = base64.b64encode(b'hello')
decoded = base64.b64decode(encoded)

binascii

Convert between binary and ASCII. Support Level: Partial Supported: hex, unhex, crc32, and other common functions Not Supported: base16, base32, base85 variants

Mathematical Operations

math

Mathematical functions. Support Level: Full support Example:

import math

result = math.sqrt(16.0)
angle = math.sin(math.pi / 2)

math.integer

Integer-specific mathematical operations. Support Level: Full support Example:

import math.integer

gcd_result = math.integer.gcd(48, 18)

random

Generate pseudo-random numbers. Support Level: Full support Example:

import random

random.seed(42)
value = random.randint(1, 10)
choice = random.choice(['a', 'b', 'c'])
random.shuffle(my_list)

Note: Uses Mersenne Twister algorithm. Use --random flag for faster rand() generator.

colorsys

Conversions between color systems. Support Level: Full support Example:

import colorsys

rgb = colorsys.hsv_to_rgb(0.5, 1.0, 1.0)

Algorithm Support

itertools

Functions creating iterators for efficient looping. Support Level: Partial Supported: count, cycle, repeat, chain, compress, dropwhile, filterfalse, groupby, islice, takewhile, tee, zip_longest, product, permutations, combinations, combinations_with_replacement, accumulate, pairwise, batched Not Supported: starmap Example:

import itertools

# Infinite counter
for i in itertools.count(10, 2):
    if i > 20:
        break
    print(i)  # 10, 12, 14, 16, 18, 20

# Combinations
for combo in itertools.combinations([1, 2, 3], 2):
    print(combo)  # (1,2), (1,3), (2,3)

functools

Higher-order functions and operations on callable objects. Support Level: Minimal (reduce only) Supported: reduce function Not Supported: partial, lru_cache, wraps, and other decorators Example:

from functools import reduce

total = reduce(lambda x, y: x + y, [1, 2, 3, 4])
print(total)  # 10

System and OS

sys

System-specific parameters and functions. Support Level: Partial Supported:

sys.argv - Command-line arguments
sys.exit() - Exit program
sys.stdin, sys.stdout, sys.stderr - Standard streams
sys.maxsize - Largest integer

Not Supported: Many introspection features, sys.modules manipulation Example:

import sys

if len(sys.argv) > 1:
    filename = sys.argv[1]
    print(f'Processing {filename}')

os

Miscellaneous operating system interfaces. Support Level: Partial Supported:

File operations: os.remove(), os.rename(), os.listdir()
Directory operations: os.mkdir(), os.rmdir(), os.getcwd(), os.chdir()
Process: os.system(), os.getpid()
Environment: os.getenv(), os.environ

Example:

import os

files = os.listdir('.')
for f in files:
    if f.endswith('.py'):
        print(f)

os.path

Common pathname manipulations. Support Level: Full support Example:

import os.path

if os.path.exists('file.txt'):
    size = os.path.getsize('file.txt')
    base = os.path.basename('file.txt')
    dir = os.path.dirname('/path/to/file.txt')

stat

Interpreting stat() results. Support Level: Full support Example:

import os
import stat

st = os.stat('file.txt')
if stat.S_ISREG(st.st_mode):
    print('Regular file')

glob

Unix style pathname pattern expansion. Support Level: Partial Supported: Basic glob patterns Not Supported: escape, translate functions Example:

import glob

py_files = glob.glob('*.py')
for f in py_files:
    print(f)

getopt

C-style command-line option parser. Support Level: Full support Example:

import getopt
import sys

opts, args = getopt.getopt(sys.argv[1:], 'ho:', ['help', 'output='])
for opt, arg in opts:
    if opt in ('-h', '--help'):
        print('Usage: ...')

Date and Time

time

Time access and conversions. Support Level: Partial Supported:

time.time() - Current time as float
time.sleep() - Sleep for seconds
time.clock() - Process time
time.strftime() - Format time

Example:

import time

start = time.time()
time.sleep(1.0)
elapsed = time.time() - start

datetime

Basic date and time types. Support Level: Partial (not well tested) Supported: date, time, datetime, timedelta classes Limitations: May have edge cases or incomplete functionality Example:

from datetime import datetime, timedelta

now = datetime.now()
tomorrow = now + timedelta(days=1)
print(tomorrow.strftime('%Y-%m-%d'))

I/O and Files

io

Core tools for working with streams. Support Level: Partial Supported:

io.BytesIO - In-memory bytes buffer
io.StringIO - In-memory string buffer

Example:

import io

buffer = io.StringIO()
buffer.write('Hello ')
buffer.write('World')
contents = buffer.getvalue()

Networking

socket

Low-level networking interface. Support Level: Partial (not well tested) Supported: Basic socket operations for TCP/UDP Limitations: May be incomplete or unstable Example:

import socket

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(('localhost', 8080))
sock.send(b'GET / HTTP/1.0\r\n\r\n')
data = sock.recv(1024)
sock.close()

select

I/O completion waiting. Support Level: Partial (not well tested) Example:

import select

ready = select.select([socket], [], [], timeout)

Memory and System

gc

Garbage collector interface. Support Level: Minimal Supported:

gc.enable() - Enable garbage collection
gc.disable() - Disable garbage collection
gc.collect() - Force collection

Example:

import gc

gc.disable()  # Disable for performance-critical section
# ... critical code ...
gc.enable()

Note: Uses Boehm GC. Use --nogc flag to disable entirely.

copy

Shallow and deep copy operations. Support Level: Partial Supported: copy, deepcopy functions Not Supported: replace function Example:

import copy

original = [[1, 2], [3, 4]]
shallow = copy.copy(original)
deep = copy.deepcopy(original)

mmap

Memory-mapped file support. Support Level: Partial (not well tested) Limitations: May have platform-specific issues Example:

import mmap

with open('file.dat', 'r+b') as f:
    mm = mmap.mmap(f.fileno(), 0)
    data = mm.read(100)
    mm.close()

signal

Set handlers for asynchronous events. Support Level: Partial Supported: Basic signal handling on Unix-like systems Example:

import signal

def handler(signum, frame):
    print('Signal received')

signal.signal(signal.SIGINT, handler)

Usage in Programs

To use any supported module in your Shed Skin program, simply import it as you would in regular Python:

import random
import re
from collections import deque

# Your code here

Module Support Summary

Module	Support Level	Notes
array	Full	Space-efficient numeric arrays
base64	Partial	No base16/32/85 variants
binascii	Partial	No base16/32/85 variants
bisect	Full	Array bisection
collections	Partial	defaultdict, deque only
colorsys	Full	Color system conversions
configparser	Partial	No SafeConfigParser
copy	Partial	No replace function
csv	Partial	ASCII-only, no Sniffer
datetime	Partial	Not well tested
fnmatch	Full	Filename patterns
functools	Minimal	reduce only
gc	Minimal	enable, disable, collect
getopt	Full	Command-line parsing
glob	Partial	No escape, translate
heapq	Full	Priority queues
io	Partial	BytesIO, StringIO
itertools	Partial	No starmap
math	Full	Mathematical functions
math.integer	Full	Integer math operations
mmap	Partial	Not well tested
os	Partial	Core functions only
os.path	Full	Path manipulations
random	Full	Pseudo-random numbers
re	Full	PCRE-compatible regex
select	Partial	Not well tested
signal	Partial	Basic signal handling
socket	Partial	Not well tested
stat	Full	File statistics
string	Partial	No Format, Template
struct	Partial	No Struct, iter_unpack
sys	Partial	Core functionality
time	Partial	Basic time functions

​Data Structures

​array

​collections

​heapq

​bisect

​Text Processing

​re

​string

​fnmatch

​File and Data Processing

​csv

​configparser

​struct

​base64

​binascii

​Mathematical Operations

​math

​math.integer

​random

​colorsys

​Algorithm Support

​itertools

​functools

​System and OS

​sys

​os

​os.path

​stat

​glob

​getopt

​Date and Time

​time

​datetime

​I/O and Files

​io

​Networking

​socket

​select

​Memory and System

​gc

​copy

​mmap

​signal

​Usage in Programs

​Module Support Summary

​See Also

Data Structures

array

collections

heapq

bisect

Text Processing

re

string

fnmatch

File and Data Processing

csv

configparser

struct

base64

binascii

Mathematical Operations

math

math.integer

random

colorsys

Algorithm Support

itertools

functools

System and OS

sys

os

os.path

stat

glob

getopt

Date and Time

time

datetime

I/O and Files

io

Networking

socket

select

Memory and System

gc

copy

mmap

signal

Usage in Programs

Module Support Summary

See Also