$ perl -le'sub x { \*STDOUT }; print x() "blah"'
String found where operator expected at -e line 1, near ") "blah""
        (Missing operator before "blah"?)
syntax error at -e line 1, near ") "blah""
Execution of -e aborted due to compilation errors.
$ perl -le'sub x { \*STDOUT }; print { x() } "blah"'
blah