[pypy-dev] pypy callback function pointer become invalid

[Yicong Huang]

Great thanks Armin! The method should work.
And I thought "exec", "compiled" and "cached" together do the quite similar
work as pypy_execute_source() does.
Yes, in theory we could do all these work by ourselves, and also could be
more flexible to chose what need to do and what need not to do.
But I think if we could wrap these work and have similar API as Python, it
would be more easier and friendly to use PyPy, especially for those users
transferring from Python to Pypy.

On Mon, Aug 17, 2015 at 9:54 PM, Armin Rigo <arigo at tunes.org> wrote:

> Hi,
>
> On 17 August 2015 at 12:59, Yicong Huang <hengha.mao at gmail.com> wrote:
> > However, to perform the python function call, we need to parse
> char*(python
> > code), a python code lexer, praser, JIT and etc, in other words do all
> the
> > work that  pypy_execute_source() did.
>
> This is done in a couple of lines in Python.  The following would do all
> this:
>
> @ffi.function("void(char *)")
> def run_function(p_src):
>     src = ffi.string(p_src)
>     glob = {}
>     exec src in glob
>
> In my previous example I used "eval" instead of "exec" only to return a
> value.
>
> If you want to be more JIT-friendly, and if run_function() is going to
> be called with the exact same p_src a lot of times, you could do
> instead:
>
> cache = {}
> @ffi.function("void(char *)")
> def run_function(p_src):
>     src = ffi.string(p_src)
>     code = cache.get(src)
>     if code is None:
>         code = compile(src, 'exec', 'exec')
>         cache[src] = code
>     glob = {}
>     exec code in glob
>
> Or maybe:
>
> cache = []
> @ffi.function("long(char *)")
> def compile_and_cache(p_src):
>     code = compile(ffi.string(p_src), 'exec', 'exec')
>     index = len(cache)
>     cache.append(code)
>     return index
>
> @ffi.function("void(long)")
> def run_compiled_function(index):
>     glob = {}
>     exec cache[index] in glob
>
>
> > So why don't PyPy expose and API to do such job ?
>
> Because PyPy only exposes an *API builder*, not a particular API.  The
> pypy_execute_source_ptr() is the bare minimal entry point, which
> you're supposed to call once and build your own API as you see fit.
> The functions above are examples of such an API.  And as shown above,
> even such a simple API has various tweaks that are better in various
> cases, like whether caching the code object is a good idea or not; you
> can implement any version you like in a few lines of Python.
>
>
> A bientôt,
>
> Armin.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/pypy-dev/attachments/20150818/cc2e37de/attachment.html>