rapcsv 0.0.1

Streaming async CSV — no fake async, no GIL stalls.

rapcsv

Streaming async CSV — no fake async, no GIL stalls.

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Why rap*?

Packages prefixed with rap stand for Real Async Python. Unlike many libraries that merely wrap blocking I/O in async syntax, rap* packages guarantee that all I/O work is executed outside the Python GIL using native runtimes (primarily Rust). This means event loops are never stalled by hidden thread pools, blocking syscalls, or cooperative yielding tricks. If a rap* API is async, it is structurally non-blocking by design, not by convention. The rap prefix is a contract: measurable concurrency, real parallelism, and verifiable async behavior under load.

See the rap-manifesto for philosophy and guarantees.

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What this package provides

• True async CSV reading and writing
• Streaming support for large files
• Native Rust-backed execution (Tokio)
• Zero Python thread pools
• Event-loop-safe concurrency under load
• GIL-independent I/O operations
• Zero-copy I/O when feasible

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Installation

pip install rapcsv

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Usage

import asyncio
from rapcsv import Reader, Writer

# TODO: Implement async API
# async def main():
#     reader = await Reader.create("input.csv")
#     writer = await Writer.create("output.csv")
#     
#     async for row in reader:
#         await writer.write_row(row)

# asyncio.run(main())

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Benchmarks

This package passes the Fake Async Detector. Benchmarks are available in the rap-bench repository.

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Non-Goals

• Not a drop-in replacement for csv module
• Not compatible with all CSV dialects (yet)
• Not designed for synchronous use cases

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License

MIT