# Python library

`python/mscb.py` implements the Ethernet/UDP MSCB transport directly. It does
not load `src/mscb.cxx`, a shared library, USB drivers, or RPC components.

`python/msc.py` finds it through Python's ordinary import mechanism:

```python
import mscb
```

When `python/msc.py` is run as a script, Python adds its containing `python/`
directory to `sys.path`, so the adjacent `python/mscb.py` is imported. No pip
installation is needed for this repository layout.

## Direct use

```python
import mscb

fd = mscb.mscb_init("192.0.2.40")
if fd < 0:
    raise ConnectionError(fd)

try:
    if mscb.mscb_ping(fd, 1) == mscb.MSCB_SUCCESS:
        print("node 1 is alive")
finally:
    mscb.mscb_exit(fd)
```

These public module functions deliberately keep the familiar C names, so
`msc.py` calls `mscb.mscb_ping(...)`, `mscb.mscb_read(...)`, and similar
functions directly. `mscb` is the imported module; the name after the dot is
an object defined in that module. It is not a dynamic link or an include
directive.

For small new programs, the optional `MSCB` context-manager façade provides
shorter `ping()`, `read()`, and `write()` methods:

```python
with mscb.MSCB("192.0.2.40") as bus:
    if bus.ping(1):
        print(bus.read(1, 0))
```

## Installation choices

For in-tree use, run:

```bash
python3 python/msc.py -d 192.0.2.40
```

For another application, either put `python/` on `PYTHONPATH`, copy/package the
module with the application, or add standard package metadata and install it.
The current source tree itself does not require a published pip package.

## XML snapshots

The Python CLI can save a node as readable XML. The writer applies element
indentation and appends a final newline, so every entry is on its own line and
the result remains friendly to version control and comparison with C-client
output.

## Scope

Only UDB/Ethernet communication is implemented. USB device discovery,
direct parallel-port access, and MSCB RPC forwarding are deliberately absent.
The node-bus protocol and typed-variable behavior remain compatible with the C
implementation.