Q: Name of a arbitary variable as a string?

[Jeff Epler]

On Tue, Nov 12, 2002 at 09:01:28PM +0100, username wrote:
> I am searching for a function (call it: var_name) that do something like
> this: 
> 
> >>> V="Hello World"
> >>> var_name(V)
> 'V'

Here's a very nasty little piece of work which makes a few assumptions
about the kindly nature of the caller and the structure of Python
bytecodes.

I recommed that you not use this code.  You should probably find another
way to do whatever it is you're trying to do.  For instance, you could
replace
    var_name(V)
with
    "V"

BTW, this code is broken at least for LOAD_DEREF and probably for
LOAD_NAME.  

# IF YOU USE THIS CODE YOU WILL DIE
def var_name(arg):
    f = sys._getframe(1)
    c = f.f_code.co_code
    ip = f.f_lasti
    i = ord(c[ip-3])
    o = ord(c[ip-2]) + 256*ord(c[ip-1])
    r = []
    while dis.opname[i] == 'LOAD_ATTR':
	r.append(f.f_code.co_names[o])
	ip=ip-3
	i = ord(c[ip-3])
	o = ord(c[ip-2]) + 256*ord(c[ip-1])
    if dis.opname[i] == 'LOAD_FAST':
	r.append(f.f_code.co_varnames[o])
    r.append(f.f_code.co_names[o])
    r.reverse()
    print r
    return ".".join(r)