__LINE__ and __FILE__ functionality in Python?

[Joakim Hove]

Hello,

i have simple[1] function like this:

def log_msg(msg , file , line):
print "%s:%s %s" % (file,line,msg)

the file and line arguments should be the filename and linenumber of
the source file where the function is called. If this were C I would
have used the __FILE__ and __LINE__ macros as:

log_msg(msg , __FILE__ , __LINE__)

Is there a way to emulate this behaviour in Python?


Best Regards

Joakim Hove



[1]: It is not *that* simple, but you get the point.


--
Joakim Hove
hove AT ntnu.no /
Tlf: +47 (73 5)9 34 27 / Stabburveien 18
Fax: ............... .. / N-5231 Paradis
http://www.ift.uib.no/~hove/ / 55 91 28 18 / 92 68 57 04

[Maric Michaud]

Re: __LINE__ and __FILE__ functionality in Python?

Le dimanche 13 août 2006 13:31, Joakim Hove a écrit :

Hello,
>
i have simple[1] function like this:
>
def log_msg(msg , file , line):
print "%s:%s %s" % (file,line,msg)
>
the file and line arguments should be the filename and linenumber of
the source file where the function is called. If this were C I would
have used the __FILE__ and __LINE__ macros as:
>
log_msg(msg , __FILE__ , __LINE__)
>
Is there a way to emulate this behaviour in Python?

Sure, try :

In [46]: import inspect

In [47]: c=inspect.curre ntframe()

In [48]: c.f_lineno
Out[48]: 1

In [49]: c.f_code.co_fil ename
Out[49]: '<ipython console>'

Of course, in the console, these are not truly relevant.


--
_____________

Maric Michaud
_____________

Aristote - www.aristote.info
3 place des tapis
69004 Lyon
Tel: +33 426 880 097

[John Machin]

Re: __LINE__ and __FILE__ functionality in Python?

Joakim Hove wrote:

Hello,
>
i have simple[1] function like this:
>
def log_msg(msg , file , line):
print "%s:%s %s" % (file,line,msg)
>
the file and line arguments should be the filename and linenumber of
the source file where the function is called. If this were C I would
have used the __FILE__ and __LINE__ macros as:
>
log_msg(msg , __FILE__ , __LINE__)
>
Is there a way to emulate this behaviour in Python?
>

It's better in Python not to emulate that but to let the caller do the
work:

C:\junk>type caller_id.py
import inspect

def logger(msg):
print "logger:", msg
print "called from %s:%d" % inspect.stack()[1][1:3]
print

def client1():
logger("one")

def client2():
logger("two")

client1()
client2()


C:\junk>caller_ id.py
logger: one
called from C:\junk\caller_ id.py:9

logger: two
called from C:\junk\caller_ id.py:12

If you care to search for __LINE__ in this newsgroup, there's a slight
chance you might find a thread or two or twenty-two on the topic :-)

I don't usually go for one-liners, especially ugly ones like
"inspect.stack( )[1][1:3]" but it avoids the risk of hanging on to a
reference to the frame object -- see the warning in the inspect docs.

You can get the name of the calling function or method (and,
indirectly, the method's class) if you want to log the whole dossier --
details left as an exercise :-)

HTH,
John

[Joakim Hove]

Re: __LINE__ and __FILE__ functionality in Python?


Maric Michaud <maric@aristote .infowrites:

Sure, try :
>
In [46]: import inspect
>
In [47]: c=inspect.curre ntframe()
>
In [48]: c.f_lineno
Out[48]: 1
>
In [49]: c.f_code.co_fil ename
Out[49]: '<ipython console>'

Thanks a lot - that was just what I wanted.


Regards - Joakim


--
Joakim Hove
hove AT ntnu.no /
Tlf: +47 (73 5)9 34 27 / Stabburveien 18
Fax: ............... .. / N-5231 Paradis
http://www.ift.uib.no/~hove/ / 55 91 28 18 / 92 68 57 04

[Maric Michaud]

Re: __LINE__ and __FILE__ functionality in Python?

Le dimanche 13 août 2006 14:18, John Machin a écrit :

I don't usually go for one-liners, especially ugly ones like
"inspect.stack( )[1][1:3]" but it avoids the risk of hanging on to a
reference to the frame object -- see the warning in the inspect docs.

Yes, my mistake, thanks for pointing this out, my suggestion should have been
more accurate :

import inspect

try :
c=inspect.curre ntframe()
log_msg(c.f_lin eno, c.f_code.co_fil ename)
finally :
del c

or shorter ;

from inspect import currentframe
log_msg(current frame().f_linen o,
currentframe(). f_code.co_filen ame)


--
_____________

Maric Michaud
_____________

Aristote - www.aristote.info
3 place des tapis
69004 Lyon
Tel: +33 426 880 097