mo-parsing
Another PEG Parsing Tool
Decision gist · record as of 2026-08-14
Yes, if you need a PEG parser and are comfortable with immutable ParserElement semantics. The low install friction, permissive MIT license, and lack of known vulnerabilities make it safe to try. The 290-day release gap suggests stability but not active development; use it for parsing tasks where pyparsing's API or performance is a concern, but verify performance gains match your use case before committing to a migration.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Low install friction with only two runtime dependencies (mo-dots, mo-future).
- The package is in Beta status and has not seen a release in 290 days, suggesting stable but not actively developed maintenance.
License · maintenance · safety
MIT (permissive) — MIT license is permissive, allowing commercial and private use with minimal restrictions—you may use and modify this package freely provided you retain the license notice.
last release 2025-10-28 (290 days) · last repo commit 2025-10-28 · 4 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 227,111 downloads/mo, #9,186 on PyPI
Alternatives
Verify before relying
pip install mo-parsing
from mo_parsing import Word
from mo_parsing.utils import alphas
greet = Word(alphas)("greeting") + "," + Word(alphas)("person") + "!"
result = greet.parse_string("Hello, World!")
print(dict(result)) # {'greeting': 'Hello', 'person': 'World'}- Whether performance improvements over pyparsing are significant enough to justify migration for typical use cases
- How well the package handles complex or deeply nested grammars in practice
- Community size and availability of third-party examples beyond the repository
What it is and what it does
mo-parsing is a fork of pyparsing optimized for faster parsing of PEG (Parsing Expression Grammar) languages. You define a grammar by combining predefined parser elements (Word, Literal, etc.) using Python operators, then call parse_string() to parse input text. The result is a ParseResults object that behaves like both a nested list and a dictionary, depending on how you named the matched elements.
The package emphasizes speed through regex-based optimization and faster infix operator parsing, and introduces a Whitespace context manager to control what characters are skipped and how the grammar behaves globally. It differs from pyparsing in that ParserElements are immutable—calling add_parse_action() returns a new element rather than modifying the original—and it removes backward-compatibility cruft. The main dependencies are mo-dots and mo-future, both lightweight utility packages.
Use it for
- Parse domain-specific languages (DSLs) or configuration file formats into structured data
- Build SQL or query parsers where infix operator precedence matters
- Extract and transform text with named capture groups into dictionaries for downstream processing
- Define grammar rules for log parsing or protocol message decoding
- Implement expression evaluators that need to respect operator precedence
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need a PEG parser and are comfortable with immutable ParserElement semantics.
The low install friction, permissive MIT license, and lack of known vulnerabilities make it safe to try. The 290-day release gap suggests stability but not active development; use it for parsing tasks where pyparsing's API or performance is a concern, but verify performance gains match your use case before committing to a migration.
Install
mo-parsing on PyPI
Before you install
Low install friction with only two runtime dependencies (mo-dots, mo-future). The package is in Beta status and has not seen a release in 290 days, suggesting stable but not actively developed maintenance.
License in practice
MIT license is permissive, allowing commercial and private use with minimal restrictions—you may use and modify this package freely provided you retain the license notice.
Quickstart
pip install mo-parsing
from mo_parsing import Word
from mo_parsing.utils import alphas
greet = Word(alphas)("greeting") + "," + Word(alphas)("person") + "!"
result = greet.parse_string("Hello, World!")
print(dict(result)) # {'greeting': 'Hello', 'person': 'World'}Verify before relying
- Whether performance improvements over pyparsing are significant enough to justify migration for typical use cases
- How well the package handles complex or deeply nested grammars in practice
- Community size and availability of third-party examples beyond the repository
Package facts
| License | MIT permissive |
| Python support | Not specified |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 2 packagesmo-dotsmo-future |
| Maintenance | Aging 290 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 227,111 / month, #9,186 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaLicense :: OSI Approved :: MIT LicenseProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Topic :: Software Development :: LibrariesTopic :: Software Development :: Libraries :: Python Modules |
Evidence: mo_parsing-8.694.25301-py3-none-any.whl
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