This is a continuation of a CB discussion, started by JadeNB which puzzles me too

Why does a (&) prototype only accept blocks or sub{} but not scalar coderefs?

I always thought that sub{} returns a scalar coderef.

See following code, line 36 shows a workaround from Ikegami.

But why the heck do I need an idempotent operation like \& ???

  DB<32> sub fu(&) {print shift}
  
  DB<33> fu sub {}
CODE(0x990f0a8)
  DB<34> $a= sub {}
  
  DB<35> fu $a #ERROR
Type of arg 1 to main::fu must be block or sub {} (not scalar derefere
+nce) at (eval 37)[/usr/share/perl/5.10/perl5db.pl:638] line 4, at EOF
  
  DB<36> fu \&$a #OK
CODE(0x997f168)

[download]

Cheers Rolf

UPDATE: Thanks JadeNB nice problem, I learned a lot! 8)

In reply to coderefs and (&) prototypes by LanX

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