Thanks to Autobox you can do 
use autobox::universal qw(type);

say type("42");  # STRING
say type(42);    # INTEGER
say type(42.0);  # FLOAT 
say type(undef); # UNDEF

[download]
See chocolateboy's response in "How to tell apart numeric scalars and string scalars in Perl?"

In reply to Re: How can I test for the representation of an integer? by clueless newbie
in thread How can I test for the representation of an integer? by sm@sh

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