subs - Perl pragma to predeclare sub names
use subs qw(frob);
frob 3..10;This will predeclare all the subroutine whose names are in the list, allowing you to use them without parentheses even before they're declared.
Unlike pragmas that affect the $^H hints variable, the use vars and use subs declarations are not BLOCK-scoped. They are thus effective for the entire package in which they appear. You may not rescind such declarations with no vars or no subs.
See "Pragmatic Modules" in perlmodlib and "strict subs" in strict.