[Python-Dev] Minipython

Talin talin at acm.org
Mon Sep 25 11:27:57 CEST 2006

Milan Krcmar wrote:
> Thank you people. I'm going to try to strip unneeded things and let you
> know the result.
> Along with running Python on an embedded system, I am considering two
> more things. Suppose the system to be a small Linux router, which, after
> the kernel starts, merely configures lots of parameters of the kernel
> and then runs some daemons for gathering statistics and allowing remote
> control of the host.
> Python helps mainly in the startup phase of configuring kernel according
> to a human-readable confgiuration files. This has been solved by shell
> scripts. Python is not as suitable for running external processes and
> process pipes as a shell, but I'd like to write a module (at least)
> helping him in the sense of scsh (a "Scheme shell",
> http://www.scsh.net).
> A more advanced solution is to replace system's init (/sbin/init) by
> Python. It should even speed the startup up as it will not need to run
> shell many times. To avoid running another processes, I want to "port
> them" to Python. Processes for kernel configuration, like iproute2,
> iptables etc. are often built above its own library, which can be used as
> a start point. (Yes, it does matter, at startup, routers run such processes
> hundreds times).
> Milan

One alternative you might want to look into is the language "Lua" 
(www.lua.org), which is similar to Python in some respects (also has 
some similarities to Javascript), but specifically optimized for 
embedding in larger apps - meaning that it has a much smaller footprint, 
a much smaller standard library, less built-in data types and so on. 
(For example, dicts, lists, and objects are all merged into a single 
type called a 'table', which is just a generic indexable container.) 
Lua's C API consists of just a few dozen functions.

It's not as powerful as Python of course, although it's surprisingly 
powerful for its size - it has closures, continuations, and all of the 
goodness you would expect from a modern language. Lua provides 
'meta-mechanisms' for extending the language rather than implementing 
language features directly. So even though it's not a pure 
object-oriented language, it provides mechanisms for implementing 
classes and inheritance. And it's fast, since it has less baggage to 
carry around.

It has a few warts - for example, I don't like the fact that referring 
to an undefined variable silently returns nil instead of returning an 
error, but I suppose in some environments that's a feature.

A lot of game companies use Lua for embedded scripting languages in 
their games. (Console-based games in particular have strict memory 
requirements, since there's no virtual memory on consoles.)

-- Talin

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