poyo

library0.5.0pypypi✓ verified 87d ago

Poyo is a lightweight YAML parser for Python (current version 0.5.0). It focuses on parsing a chosen subset of the YAML format, primarily designed for configuration files like those used by cookiecutter. It explicitly does not support deserialization of arbitrary Python objects, YAML serialization, or JSON compatibility. The project is in maintenance mode with infrequent updates, with the last release in July 2019, but it remains functional for its intended scope.

serialization data

pip install poyo

github ↗package ↗

INSTALL

IMPORT

SIG · POYO

poyo

serializationpythonv0.5.0

Install

1.5s avg

Import

27ms

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v0.5.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.920 runs

installs and imports cleanly · install 0.0s · import 0.029s · 17.8MB

glibc

py 3.10–3.920 runs

installs and imports cleanly · install 1.5s · import 0.026s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

parse_string

✓ from poyo import parse_string

Main function to parse a YAML string into a Python dictionary.

PoyoException

✓ from poyo import PoyoException

Custom exception raised for parsing errors.

Parses a simple YAML string using `parse_string` and demonstrates basic type conversion and multiline string handling, with error handling for parsing issues.

from poyo import parse_string, PoyoException yaml_string = """ default_context: greeting: Hello is_enabled: true count: 123 items: - apple - banana - null long_description: > This is a multiline string. It demonstrates how to handle text blocks introduced in 0.5.0. """ try: config = parse_string(yaml_string) print(config) # Expected output similar to: # { # 'default_context': { # 'greeting': 'Hello', # 'is_enabled': True, # 'count': 123, # 'items': ['apple', 'banana', None] # }, # 'long_description': 'This is a multiline string. It demonstrates how to handle text blocks introduced in 0.5.0.' # } except PoyoException as e: print(f"Error parsing YAML: {e}")

Debug

Known issues

gotchaPoyo only supports a *subset* of the YAML specification. It does not support arbitrary Python object deserialization, YAML serialization, or compatibility with JSON. Attempting to use advanced YAML features (e.g., anchors, tags, complex mappings) will likely result in parsing errors.

fix

Ensure your YAML adheres to the basic structure supported by Poyo (scalars, lists, dictionaries). For full YAML specification support, consider libraries like PyYAML.

affects: All versions

gotchaThe `~` character (YAML's representation for null) was not correctly recognized as `None` in Python before version 0.3.0, leading to unexpected string values.

fix

Upgrade to `poyo>=0.3.0` to ensure `~` is correctly parsed as `None`.

affects: <0.3.0

gotchaEarlier versions had bugs with parsing list items that included comments or blank lines, leading to incorrect or incomplete data structures.

fix

Upgrade to `poyo>=0.4.2` to resolve issues with lists containing comments and blank lines.

affects: <0.4.2

gotchaMultiline strings using the `>` or `|` block scalar indicators are only supported in version 0.5.0 and later.

fix

Upgrade to `poyo>=0.5.0` to use multiline string features. For older versions, represent long strings as single-line quoted strings.

affects: <0.5.0

Errors

Common errors & fixes

poyo.PoyoException: Error parsing YAML: Line ... Column ...: Expected a mapping or sequence start

Attempting to parse YAML that uses features outside of Poyo's supported subset (e.g., YAML tags, anchors/aliases, or malformed syntax).

fix

Review the YAML content and simplify it to basic key-value pairs, lists, and scalars. If advanced YAML features are required, switch to a full-featured YAML parser like `PyYAML`.

KeyError: 'some_key' or AttributeError: 'NoneType' object has no attribute 'get'

A YAML `null` value (represented by `~` or `null`) was not parsed as Python's `None`, but as a string, or a key was expected but not found due to a parsing error in older versions.

fix

This often occurs in older versions of poyo. Ensure you are using `poyo>=0.3.0` to correctly handle `null` values. Also, verify that your YAML structure matches the expected Python dictionary access path.

Error parsing YAML: Line ... Column ...: Could not parse scalar

This error can occur when Poyo encounters unexpected characters or structures, such as unquoted strings containing special characters or improper indentation, especially in older versions when list/comment handling was less robust.

fix

Check for correct YAML indentation and ensure all strings with special characters or spaces are properly quoted. Consider upgrading to the latest Poyo version (`0.5.0`) as several parsing bugs were fixed in later releases.

Upgrade

Version history

0.5.0latest on PyPI · released Jul 26, 2019

Audit

Dependencies

pythonrequiredRuntime environment

Agent activity

11 hits · last 30 days

node

Resources

githubhttps://github.com/hackebrot/poyo ↗

packagehttps://pypi.org/project/poyo/ ↗