Computerwelt

Standard library

A permitted subset, not a sandboxed copy of the whole thing. A module is here because it is useful for the kind of code this runtime exists to run, and because it can be implemented without reaching outside the sandbox.

Module Notes
json dumps, loads, and the usual options
re pattern matching, substitution, splitting
math the numeric functions and constants
datetime date, time, datetime, timedelta, driven by the host's TimeProvider
collections Counter, defaultdict, deque, OrderedDict, namedtuple
dataclasses @dataclass and field
io in-memory streams
os, os.path over the virtual filesystem
pathlib over the same filesystem
glob, fnmatch pattern matching against the same filesystem
sys argv, stdin, stdout, stderr, exit, platform, version
unicodedata character properties
asyncio the subset upstream supports

Filesystem-backed modules

open, os, os.path, pathlib, glob and fnmatch all go through the host's IFileSystem. When the joined Computerwelt package is used, that is the same filesystem the shell sees, so a file a command wrote is a file the program opens, under the same quotas and the same POSIX paths.

With no filesystem configured, these raise OSError rather than failing in a way the program cannot name.

import os

for name in sorted(os.listdir('/data')):
    with open(f'/data/{name}') as handle:
        print(name, len(handle.read()))

os.walk and os.scandir are among the things this port adds beyond upstream Monty, along with glob, fnmatch, io and sys.argv. They live in their own fixture folder in the repository precisely so that a reader can tell a port decision from the upstream specification.

Reporting what is missing

import of a module that is not here raises ImportError naming it. As with the language subset, that is a message a model can act on.

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