How does one get the name of a passed scalar?

princepawn has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: How does one get the name of a passed scalar? by japhy (Canon) on May 23, 2001 at 22:37 UTC
You can't figure that out unless you pass the typeglob. `print foo{PACKAGE} . "::" . foo{NAME};` [download] `japhy` -- Perl and Regex Hacker	[reply] [d/l]
(tye)Re: How does one get the name of a passed scalar? by tye (Sage) on May 24, 2001 at 09:06 UTC
Ah, the best I could come up with for that was an editor macro that inserts: `print "$_=(".eval($_).")\n" for qw( );` and then you type any variable names you like into the qw() part. BTW, you can't just make this a Perl function as most variables of most worth-while programs won't be available for the subroutine to access by using eval on their name. Also, if you want this to work for arrays as well: `print "$_=(".eval(qq("$_")).")\n" for qw( );` and if you want this to work for hashes and other types of expressions: `print "$_=(".join(",",eval$_).")\n" for qw( );` so I'd probably just use that last one. - tye (but my friends call me "Tye")	[reply] [d/l] [select]
Re: How does one get the name of a passed scalar? by merlyn (Sage) on May 24, 2001 at 00:12 UTC
You can't, in general. What would it do with this: `tellme_my_typeglob ${ \42 }; # should output... what?` [download] What problem are you trying to solve, the solution of which involved solving this problem? Because I think you'll have to back up a step. -- Randal L. Schwartz, Perl hacker	[reply] [d/l]
Re: How does one get the name of a passed scalar? by Dr. Mu (Hermit) on May 24, 2001 at 07:57 UTC
Why don't you go about it the other way? Pass the name of the variable and use eval to get its value: `$test = 123; echoprint('$test'); sub echoprint { print "$_[0] = ".eval($_[0]) }` [download] Just don't forget to use single quotes when you call eshoprint!	[reply] [d/l]
Re: How does one get the name of a passed scalar? by princepawn (Parson) on May 23, 2001 at 22:54 UTC
maybe a source filter of some sort? Ie, Filter::Simple might be the way to go.	[reply]
Re: How does one get the name of a passed scalar? by princepawn (Parson) on May 24, 2001 at 01:19 UTC
I'm just sick of echo-printing my code like this: `$x = <>; print "x = $x";` [download] So I wanted to have a subroutine which did this: `$x = <>; echo_print $x; # results in "x = (value of $x)";` [download]	[reply] [d/l] [select]