flexparser

What it is and what it does

flexparser is a parser framework that lets you define custom statement types as frozen dataclasses with a `from_string` classmethod. Instead of writing a traditional recursive-descent or grammar-based parser, you write one class per statement type and the framework handles iteration, error collection, and file I/O. Each parsed statement is automatically annotated with line and column positions, raw text, and a content hash.

The framework distinguishes between statements the parser doesn't recognize (returns None), valid statements, and parsing errors (subclasses of ParsingError). It also supports grouping statements into blocks with begin/end markers. The result is a sequence of typed objects you can iterate over, making downstream processing type-safe and straightforward. It depends only on typing-extensions and requires Python 3.9 or later.

Use it for

• Parse domain-specific languages or configuration formats where each line type maps to a distinct dataclass.
• Build error-tolerant parsers that collect all parsing failures and continue, reporting them at the end.
• Parse structured text files (logs, reports, DSLs) where you want position tracking and type safety without writing a grammar.
• Validate and extract data from line-oriented text where different line patterns need different handling logic.

Worth the install?

AI-flagged interpretation of the facts on this page. Verify before relying on it.

Install

flexparser on PyPI

Before you install

Low friction: pure Python wheel with only typing-extensions as a runtime dependency. Maintenance is dormant—last release was 2024-11-07 and last commit 2024-11-09, with no recent activity; the package is stable but not actively developed.

License in practice

BSD-3-Clause is permissive and imposes no significant restrictions on use or redistribution, making it suitable for most commercial and open-source projects.

Quickstart

pip install flexparser

from dataclasses import dataclass
import flexparser as fp

@dataclass(frozen=True)
class Assignment(fp.ParsedStatement):
    lhs: str
    rhs: str
    
    @classmethod
    def from_string(cls, s):
        if "<-" not in s:
            return None
        lhs, rhs = s.split("<-")
        return cls(lhs.strip(), rhs.strip())

parsed = fp.parse("file.txt", Assignment)
for statement in parsed.iter_statements():
    print(statement)

Package facts

Evidence: flexparser-0.4-py3-none-any.whl

Tags

More Libraries packages

See also construct-classes · argparse-dataclass · databind · simple-parsing · rply · dataclass-factory · dacite · databind.json · typed-json-dataclass · dataclasses