The Python subset

pyscriptc compiles a deliberately strict subset of Python.
When a construct is not supported, compilation stops with a PSxxxx fence that names the exact line, it never guesses.
This page is the practical summary; the full contract lives in docs/supported.md in the repo.

Everyday Python that compiles

• print(...), including sep and end
• sys.argv as list[str], sys.platform, sys.exit
• with open(path) as f: and f.read(), f.write(...)
• for over range, lists, dict keys, and tuple literals; break and continue
• Slices, including negative steps (s[::-1])
• sorted(xs, key=lambda x: ...) for the common key cases
• if / elif / else, mixed and / or in value position
• Comprehensions over one for without filters
• f-strings with simple interpolations, %s and %d formatting
• try / except ValueError: and except Exception: (the exception model is growing milestone by milestone)
• Single-file programs and directories resolved as a package
• A broad set of str, list, dict, int, float, bytes, and pathlib.Path methods, plus scalar casts like int("42")

What stays fenced

• argparse, requests, and most imports outside the lowered stdlib table
• **kwargs, user decorators, super(), multiple inheritance, starred calls
• finally, except ... as e (for now)
• with statements other than open(...) and importlib.resources.as_file(...)
• Non Latin-1 string literals
• Async, threads, dynamic getattr on non-literal names, eval/exec

Checking your own code

Run pyscriptc coverage FILE to get a per-line fence report before compiling, or pyscriptc explain PS2001 to look up what a fence code means and the smallest rewrite that clears it.