Stpr

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Stpr (probably pronounced "steeper") is an experimental library for structured parallelism in Python. It combines the efficiency of the asyncio library with the intuitiveness of sequential programming.

Stpr works by dynamically re-compiling functions and methods. The @stpr.fn decorator parses the source code of the function it decorates, analyzes the Abstract Syntax Tree (AST), transforms it, and transparently compiles the resulting AST to bytecode. This allows it to augment the standard Python semantics and introduce new parallelism constructs.

A simple example is running functions in parallel:

import asyncio
import stpr
import time

@stpr.fn
def a():
    stpr.wait(1)

async def b():
    await asyncio.sleep(1)

def c():
    time.sleep(1)

@stpr.fn
def parallel():
    with stpr.parallel:
        a()
        b()
        c()

stpr.run(parallel)

Stpr-decorated functions are coroutines. Stpr schedules coroutines, such as a() and b() in an asyncio event loop. Synchronous functions, such as c are run in a thread pool.

Another example is starting a server socket, accepting, and handling connections:

import stpr

@stpr.fn
def handle_connection(conn):
    ...

@stpr.fn
def server():
    with stpr.Socket('localhost', 8080) as sock:
        with stpr.parallelFor(sock.connections()) as conn:
            handle_connection(conn)

stpr.run(server)