while ( <> ) already defaults to STDIN.

$ t() { perl -Mv5.10 -e'while (<>) { chomp; say "<$_>"; }' "$@"; }

$ t \
   <( echo 'Contents of virtual file 1' ) \
   <( echo 'Contents of virtual file 2' )
<Contents of virtual file 1>
<Contents of virtual file 2>

$ echo 'Contents of virtual file' | t
<Contents of virtual file>
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