Re: Line numbers

Don't use __LINE__.
Instead use [caller(0)]->[2].

See the documentation for the caller function in perlfunc.

Full example:

sub fatal_error {
  print STDERR "ERROR: ", @_," ",[caller(0)]->[2];
  usage();
  exit 1;
}
[download]

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

Comment on Re: Line numbers Select or Download Code

Replies are listed 'Best First'.
Re^2: Line numbers by LanX (Saint) on Mar 16, 2012 at 23:18 UTC
is there any advantage of `[caller(0)]->[2]` over `(caller(0))[2]`? Cheers Rolf	[reply] [d/l] [select]
Re^3: Line numbers by tobyink (Canon) on Mar 16, 2012 at 23:33 UTC
Indeed there is an advantage of the first - I can remember the syntax. It is non-obvious why `(caller(0))[2]` should work but `caller(0)[2]` should fail. Also, the arrayref plays nicer associativity wise. Check this out: `$ perl -E'sub x { say [caller(0)]->[0] } x()' main $ perl -E'sub x { say (caller(0))[0] } x()' syntax error at -e line 1, near ")[" Execution of -e aborted due to compilation errors.` [download] The version with the arrayref just acts more predictably in my mind. I don't have to waste time thinking about it. `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l] [select]
Re^4: Line numbers by chromatic (Archbishop) on Mar 17, 2012 at 00:02 UTC
It is non-obvious why `(caller(0))[2]` should work but `caller(0)[2]` should fail. Precedence.	[reply] [d/l] [select]
Re^5: Line numbers by tobyink (Canon) on Mar 17, 2012 at 00:12 UTC
Re^6: Line numbers by chromatic (Archbishop) on Mar 17, 2012 at 00:42 UTC
Re^6: Line numbers by Anonymous Monk on Mar 17, 2012 at 00:39 UTC
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Re^5: Line numbers by LanX (Saint) on Mar 17, 2012 at 00:07 UTC
Re^5: Line numbers by gg48gg (Sexton) on Mar 17, 2012 at 01:46 UTC
Re^6: Line numbers by LanX (Saint) on Mar 17, 2012 at 02:04 UTC
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Re^6: Line numbers by Anonymous Monk on Mar 17, 2012 at 02:10 UTC
Re^4: Line numbers by LanX (Saint) on Mar 17, 2012 at 00:08 UTC
Thanks! Personally I don't like referencing for immediate dereferencing. But that's a matter of taste... Anyway I'd rather prefer a clean named argument solution instead of those silly positional parameters of caller. Cheers Rolf	[reply]
Re^5: Line numbers by repellent (Priest) on Mar 17, 2012 at 06:51 UTC
Re^2: Line numbers by gg48gg (Sexton) on Mar 16, 2012 at 23:12 UTC
AWESOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! THANKS!!!!!!!!!!!!!!!	[reply]

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