Merge pull request #18 from benoitc/feature/channel-api

Add asyncio-compatible Channel API

Author: benoitc

CHANGELOG.md

@@ -2,9 +2,22 @@
 
 ## Unreleased
 
-<<<<<<< HEAD
 ### Added
 
+- **Channel API** - Bidirectional message passing between Erlang and Python
+  - `py_channel:new/0,1` - Create channels with optional backpressure (`max_size`)
+  - `py_channel:send/2` - Send Erlang terms to Python (returns `busy` on backpressure)
+  - `py_channel:close/1` - Close channel, signals `StopIteration` to Python
+  - Python `Channel` class with sync and async interfaces:
+    - `channel.receive()` - Blocking receive (suspends Python, yields to Erlang)
+    - `channel.try_receive()` - Non-blocking receive
+    - `await channel.async_receive()` - Asyncio-compatible receive
+    - `for msg in channel:` - Sync iteration
+    - `async for msg in channel:` - Async iteration
+  - `erlang.channel.reply(pid, term)` - Send messages to Erlang processes
+  - Zero-copy IOQueue buffering via `enif_ioq`
+  - 8x faster than Reactor for small messages, 2x faster for 16KB messages
+
 - **OWN_GIL Subinterpreter Thread Pool** - True parallelism with Python 3.12+ subinterpreters
   - Each subinterpreter runs in its own thread with its own GIL (`Py_GIL_OWN`)
   - Thread pool manages N subinterpreters for parallel Python execution

c_src/py_callback.c

@@ -2400,9 +2400,15 @@ static int create_erlang_module(void) {
         "        erlang.ExecutionMode = _erlang_impl.ExecutionMode\n"
         "        # Reactor for fd-based protocol handling\n"
         "        erlang.reactor = _erlang_impl.reactor\n"
+        "        # Channel for bidirectional message passing\n"
+        "        erlang.channel = _erlang_impl.channel\n"
+        "        erlang.Channel = _erlang_impl.Channel\n"
+        "        erlang.ChannelClosed = _erlang_impl.ChannelClosed\n"
+        "        erlang.reply = _erlang_impl.reply\n"
         "        # Make erlang behave as a package for 'import erlang.reactor' syntax\n"
         "        erlang.__path__ = [priv_dir]\n"
         "        sys.modules['erlang.reactor'] = erlang.reactor\n"
+        "        sys.modules['erlang.channel'] = erlang.channel\n"
         "        return True\n"
         "    except ImportError as e:\n"
         "        import sys\n"