PyMeta3
Pattern-matching language based on OMeta for Python 3 and 2
Decision gist · record as of 2026-08-14
No—unless you are maintaining legacy code already using PyMeta3. The package is abandoned (last commit 2019-01-09, no releases since 2015-02-22), has high install friction, and its Python 3 compatibility is unverified beyond Python 3.4. Consider actively maintained alternatives for new projects.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- No explicit Python version requirement stated; classifiers list Python 2.7, 3.3, and 3.4, but compatibility with modern Python versions is unverified.
- Installation friction is high due to source distribution only; the package is abandoned (last commit 2019-01-09, no releases since 2015-02-22), so expect no maintenance or bug fixes.
License · maintenance · safety
MIT License (permissive) — MIT License permits commercial and private use with minimal restrictions, making it legally safe to adopt if you accept the maintenance risk.
last release 2015-02-22 (4191 days) · last repo commit 2019-01-09 · 18 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 659,021 downloads/mo, #5,465 on PyPI
Alternatives
Verify before relying
from pymeta.grammar import OMeta
grammar = """ones ::= '1' '1' => 1
twos ::= '2' '2' => 2
stuff ::= ( | )+"""
Example = OMeta.makeGrammar(grammar, {})
g = Example("11221111")
result, error = g.apply("stuff")- Whether PyMeta3 actually works on Python 3.5+ despite classifiers only listing up to 3.4
- Whether the package has been tested or used successfully in recent years given the 2019 last commit
- Whether high install friction reflects build complexity or is merely a packaging choice
What it is and what it does
PyMeta3 is a pattern-matching language implementation based on OMeta, an object-oriented grammar formalism. It lets you define parsing rules using a compact PEG-like syntax and compiles them into Python classes with methods corresponding to grammar rules. Each rule specifies parsing expressions that consume input and return values on successful match.
The package is useful for building parsers, lexers, and tree transformers without writing imperative parsing code. You define rules declaratively (e.g., `foo ::= 'x' 'y' => result`), and PyMeta3 handles the matching logic. It has no runtime dependencies, but the project is no longer maintained—the last release was 2015-02-22 and the repository shows no activity since 2019-01-09.
Use it for
- Build a simple expression parser or calculator by defining grammar rules for operators and operands
- Implement a domain-specific language (DSL) lexer and parser without hand-coding recursive descent logic
- Transform structured text or code by parsing it into a tree and applying pattern-matching rules
- Prototype a language or configuration file parser quickly using declarative grammar syntax
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
No—unless you are maintaining legacy code already using PyMeta3.
The package is abandoned (last commit 2019-01-09, no releases since 2015-02-22), has high install friction, and its Python 3 compatibility is unverified beyond Python 3.4. Consider actively maintained alternatives for new projects.
Install
pymeta3 on PyPI
Before you install
Installation friction is high due to source distribution only; the package is abandoned (last commit 2019-01-09, no releases since 2015-02-22), so expect no maintenance or bug fixes.
No explicit Python version requirement stated; classifiers list Python 2.7, 3.3, and 3.4, but compatibility with modern Python versions is unverified.
License in practice
MIT License permits commercial and private use with minimal restrictions, making it legally safe to adopt if you accept the maintenance risk.
Quickstart
from pymeta.grammar import OMeta
grammar = """ones ::= '1' '1' => 1
twos ::= '2' '2' => 2
stuff ::= ( | )+"""
Example = OMeta.makeGrammar(grammar, {})
g = Example("11221111")
result, error = g.apply("stuff")Verify before relying
- Whether PyMeta3 actually works on Python 3.5+ despite classifiers only listing up to 3.4
- Whether the package has been tested or used successfully in recent years given the 2019 last commit
- Whether high install friction reflects build complexity or is merely a packaging choice
Package facts
| License | MIT License permissive |
| Python support | Not specified |
| Install friction | High. Source build required |
| Runtime dependencies | None |
| Maintenance | Abandoned 4,191 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 659,021 / month, #5,465 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaIntended Audience :: DevelopersLicense :: OSI Approved :: MIT LicenseOperating System :: OS IndependentProgramming Language :: Python :: 2Programming Language :: Python :: 2.7Programming Language :: Python :: 3Programming Language :: Python :: 3.3Programming Language :: Python :: 3.4 |
Evidence: PyMeta3-0.5.1.tar.gz
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