{"categories":[{"label":"Python Modules","url":"https://skillfed.io/packages/category/software-development-libraries-python-modules/19"},{"label":"Linguistic","url":"https://skillfed.io/packages/category/text-processing-linguistic/2"}],"enrichment":{"capability":"Pyleri is a left-right parser generator that lets you define a grammar in Python and parse strings against it, with the ability to export that grammar to JavaScript, C, Go, and Java.","skillfed_tags":["parser-generator","cross-language","grammar-definition"],"use_cases":["Define a query language grammar once in Python and export it to JavaScript for browser-side validation and autocompletion","Validate domain-specific language (DSL) syntax in a Python application before processing","Build a parser for a custom configuration file format and reuse it across Python, C, and Go microservices","Generate error messages showing what tokens are expected at a parse failure position","Create a grammar for a database query language and export it to multiple client libraries"],"what_it_does":"Pyleri is a parser generator that lets you define a formal grammar as a Python class, then use it to parse and validate strings. You compose grammars from building blocks like Keywords, Regex patterns, Sequences, and Choices, then call parse() to check whether a string matches. The parser returns a result object with validation status, position, parse tree, and error expectations.\n\nThe package's main strength is cross-language export: once you define a grammar in Python, you can generate equivalent parsers in JavaScript (via jsleri), C (via libcleri), Go (via goleri), and Java (via jleri). This makes it useful for projects that need consistent parsing logic across multiple codebases\u2014for instance, a web app with a Python backend and JavaScript frontend, or a database query language that needs to validate input in multiple services.","worth_installing":"Yes. Pyleri is actively maintained, has no dependencies, installs easily, carries no security vulnerabilities, and solves a real problem\u2014defining grammars once and reusing them across languages. It's most valuable if you need consistent parsing logic in multiple codebases; for single-language parsing, a simpler tool may suffice."},"id":"pyleri","links":{"html":"https://skillfed.io/packages/pyleri","md":"https://skillfed.io/packages/pyleri.md","pypi":"https://pypi.org/project/pyleri/"},"maintenance":{"status":"active"},"meta":{"latest_release":"2026-07-06","license_spdx":null,"license_treatment":"permissive","name":"pyleri","python_support":"unspecified","summary":"Python Left-Right Parser"},"popularity":{"monthly_downloads":124563,"position":11863,"tier":"top_15000"},"security":{"n_vulnerabilities":0},"version":"1.5.1"}