There are at least two reasons that I can think of..
  1. caller: 
    sub whoami {
    print +(caller 1)[3], $/
}
                                                                      
+          
*main::foo = sub { whoami() };
                                                                      
+          
foo();

__END__
main::__ANON__

    [download]
  2. DProf: 
    *main::foo = sub { sleep 1; };
                                                                      
+          
foo() for 1..5;

__END__
$ perl -d:DProf foo.pl
$ dprofpp tmon.out
Total Elapsed Time =  5.00996 Seconds
  User+System Time =        0 Seconds
Exclusive Times
%Time ExclSec CumulS #Calls sec/call Csec/c  Name
 0.00       - -0.000      5        -      -  main::__ANON__

    [download]
When you have a lot of different anonymous subs floating around, it's a pain in the butt to profile, because all calls to anonymous subs land in main::__ANON__ as far as DProf is concerned.

There's a trick involving local *__ANON__, which works for caller but not DProf.

blokhead

In reply to Re^2: Naming Anonymous Subs by blokhead
in thread Naming Anonymous Subs by fluffy

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