pocketpy/docs/modules/inspection.md

---

icon: package

label: inspect and dis

inspect and dis

Inspect function metadata and the bytecode that pocketpy executes.

inspect

Function	Behavior
isgeneratorfunction(obj)	Whether a Python function or bound method is a generator function.
is_user_defined_type(type)	Whether a type was created by a Python class statement.
signature(callable)	A Signature with an ordered parameters dictionary for supported callables.

import inspect

def countdown(start, step=1):
    while start > 0:
        yield start
        start -= step

assert inspect.isgeneratorfunction(countdown)
signature = inspect.signature(countdown)
assert str(signature) == '(start, step=1)'
assert signature.parameters['step'].default == 1

Each Parameter exposes name, kind, and default. Parameter.empty marks a missing default. The kind constants use the familiar POSITIONAL_ONLY, POSITIONAL_OR_KEYWORD, VAR_POSITIONAL, KEYWORD_ONLY, and VAR_KEYWORD names.

Signature metadata does not override pocketpy's argument rules. In particular, the positional-or-keyword label is not a guarantee that a required parameter can be passed by name.

Signature support is limited to Python functions and compatible wrappers, bound methods, and class initializers. Not all built-in/native callables have signatures. General source inspection, binding arguments to a signature, and annotation introspection are not implemented.

dis

dis.dis(function_or_code) prints a bytecode listing and returns None:

import dis

def double(value):
    return value * 2

dis.dis(double)

Opcodes are specific to pocketpy and may change between versions. Use the output to understand execution, not as a stable serialization format.

Implementations: inspect.py, inspect.c, dis.c.