On 03/08/2016 14:31, Chris Angelico wrote:
On Wed, Aug 3, 2016 at 11:23 PM, BartC <b...@freeuk.com> wrote:
On 03/08/2016 09:58, Steven D'Aprano wrote:
Python is sometimes described as a Lisp with more sensible syntax, so its
not
surprising that it is relatively simple to translate Python to Lisp and
visa
versa.
Translating Python would be easier if everything was implemented as Python.
But sometimes you try to find a .py import module and it doesn't seem to
exist anywhere. (sys.py for example).
I would like to see how such references are translated to Lisp.
Ultimately, you _cannot_ implement everything in Python, unless you
create some sort of crazy fudge like having function pointers with
real language support, in which case you're writing C code. Some
modules have to be implemented in the host language (C for CPython,
Java for Jython, etc), in order to provide lower-level functionality.
You probably *could* implement the whole math module in pure Python,
but you don't want to; and cryptography, likewise, you theoretically
could implement in pure Python, and you'd get the same return value,
but you risk opening yourself up to timing-based attacks.
How, from Lisp, would you call on OpenSSL or another lower-level
library? Or do you have to reimplement everything? What about simple
things like opening files, how do you do that without native code?
The approach I use is to provide direct access, from the language, to
external .dll or .so files.
Then it is possible, with a suitable interface *written in the byte-code
language*, to directly call C's fopen() for example.
I believe Python also has a means of directly calling DLLs, so that in
theory its file system can be build on top of the C runtime (msvcrt.dll
or Linux' equivalent).
There still needs to be some magic support for this mechanism, but more
can be written in Python.
--
Bartc
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