Determining the type of a subroutine parameter

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

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Re: Determining the type of a subroutine parameter by moritz (Cardinal) on Aug 18, 2008 at 14:51 UTC
You can use ref or Scalar::Util`::reftype`.	[reply] [d/l]
Re: Determining the type of a subroutine parameter by FunkyMonk (Bishop) on Aug 18, 2008 at 14:51 UTC
Have a look at ref `my ( $scalar, @array ); foo( \$scalar ); foo( \@array ); sub foo { print ref $_[0], "\n"; } __END__ SCALAR ARRAY` [download] Unless I state otherwise, all my code runs with strict and warnings	[reply] [d/l]
Re: Determining the type of a subroutine parameter by Bloodnok (Vicar) on Aug 18, 2008 at 15:11 UTC
I don't think that quite answers the OP i.e. from the POV of a scalar variable - to use the given example ... `sub foo { print "Type: ", ref $_[0], "\n"; } my ( $scalar, @array ); foo( $scalar ); foo( \$scalar ); foo( \@array ); __END__ Type: Type: SCALAR Type: ARRAY` [download] This to determine if a scalar has been passed, calling `ref` on it will return the empty string. HTH , A user level that continues to overstate my experience :-))	[reply] [d/l] [select]