=over =item sub NAME BLOCK X =item sub NAME (PROTO) BLOCK =item sub NAME : ATTRS BLOCK =item sub NAME (PROTO) : ATTRS BLOCK This is subroutine definition, not a real function I. Without a BLOCK it's just a forward declaration. Without a NAME, it's an anonymous function declaration, so does return a value: the CODE ref of the closure just created. See L and L for details about subroutines and references; see L and L for more information about attributes. =back