interpreter frame

[Leo]

Why is it not possible to get the frame from the interpreter using the
inspect library? IOW, why does this code:
[color=blue][color=green][color=darkred]
>>> from inspect import *
>>> stack()[/color][/color][/color]

produce:

[(<frame object at 0x81b6d94>, '<stdin>', 1, '?', None, None)]

instead of:

[(<frame object at 0x81b6d94>, '<stdin>', 1, '?', '\tstack()', 0)]

?

I must be missing something. The motivating question is:

How can I get the interpreter line that triggered the current actions?

TIA,
Leo.

[Peter Hansen]

Re: interpreter frame

Leo wrote:[color=blue]
> Why is it not possible to get the frame from the interpreter using the
> inspect library?[/color]

Because sys._getframe() does the job instead?

-Peter

[Leo]

Re: interpreter frame

Good try, but that doesn't seem to work either. Maybe I should have
emphasized that what I really want is the line of code, as opposed to
the entire frame. Here is the output of sys._getframe() on my system:

Python 2.3.4 (#1, Feb 2 2005, 12:11:53)
[GCC 3.4.2 20041017 (Red Hat 3.4.2-6.fc3)] on linux2
Type "help", "copyright" , "credits" or "license" for more information.[color=blue][color=green][color=darkred]
>>> import sys
>>> sys._getframe()[/color][/color][/color]
<frame object at 0x9fbce0c>[color=blue][color=green][color=darkred]
>>> from inspect import *
>>> getframeinfo(sy s._getframe())[/color][/color][/color]
('<stdin>', 1, '?', None, None)

Is it different in 2.4? Maybe there is something else in sys.* that I
am having trouble finding?

TIA,
Leo.

[Bengt Richter]

Re: interpreter frame

On 10 Aug 2005 15:08:21 -0700, "Leo" <leo.uaz@gmail. com> wrote:
[color=blue]
>Good try, but that doesn't seem to work either. Maybe I should have
>emphasized that what I really want is the line of code, as opposed to
>the entire frame. Here is the output of sys._getframe() on my system:
>
>Python 2.3.4 (#1, Feb 2 2005, 12:11:53)
>[GCC 3.4.2 20041017 (Red Hat 3.4.2-6.fc3)] on linux2
>Type "help", "copyright" , "credits" or "license" for more information.[color=green][color=darkred]
>>>> import sys
>>>> sys._getframe()[/color][/color]
><frame object at 0x9fbce0c>[color=green][color=darkred]
>>>> from inspect import *
>>>> getframeinfo(sy s._getframe())[/color][/color]
>('<stdin>', 1, '?', None, None)
>
>Is it different in 2.4? Maybe there is something else in sys.* that I
>am having trouble finding?
>[/color]
Isn't there some requirement of having a source file in order to get
the line of code, which an interactive session does not satisfy?
(Maybe a strategically located StringIO instance encapsulating the latest
interactive chunk as "source file" could solve it?)

Regards,
Bengt Richter

[Peter Hansen]

Re: interpreter frame

Leo wrote:[color=blue]
> Good try, but that doesn't seem to work either. Maybe I should have
> emphasized that what I really want is the line of code, as opposed to
> the entire frame.[/color]

Ah, it wasn't clear from your first post that you were specifically
interested in a line you entered at the *interactive prompt*. The word
"interprete r" is sometimes applied to the virtual machine, so I thought
you just wanted the current frame inside an application.

For the "interactiv e interpreter", I doubt the line of code that you are
executing is preserved anywhere (at least not in a supported, documented
fashion) as source, so I don't think there's a simple way to get at it.
Certainly not (I believe) through the frame or code object. Maybe
checking the source will lead to a hack solution...

-Peter

[Fernando Perez]

Re: interpreter frame

Peter Hansen wrote:
[color=blue]
> Leo wrote:[color=green]
>> Good try, but that doesn't seem to work either. Maybe I should have
>> emphasized that what I really want is the line of code, as opposed to
>> the entire frame.[/color]
>
> Ah, it wasn't clear from your first post that you were specifically
> interested in a line you entered at the *interactive prompt*. The word
> "interprete r" is sometimes applied to the virtual machine, so I thought
> you just wanted the current frame inside an application.
>
> For the "interactiv e interpreter", I doubt the line of code that you are
> executing is preserved anywhere (at least not in a supported, documented
> fashion) as source, so I don't think there's a simple way to get at it.
> Certainly not (I believe) through the frame or code object. Maybe
> checking the source will lead to a hack solution...[/color]

If using the mock interpreter in code.py (in the stdlib), the object's .buffer
attribute holds that info as a list of lines. IPython exposes it publicly via
its custom exception handlers mechanism (some details here:
http://www.scipy.org/wikis/featurerequests/IPython).

Such a buffer must also exist in the CPython interactive interpreter, but I
don't think it's accessible in any way via Python-level functionality (it's
most likely an internal C variable). But some perusing of the C sources could
indicate a way to get to it, I'm just not familiar with that particular code.

Cheers,

f