PPI::Statement::Sub(3) Subroutine declaration


  isa PPI::Statement
      isa PPI::Node
          isa PPI::Element


Except for the special BEGIN, CHECK, UNITCHECK, INIT, and END subroutines (which are part of PPI::Statement::Scheduled) all subroutine declarations are lexed as a PPI::Statement::Sub object.

Primarily, this means all of the various "sub foo {}" statements, but also forward declarations such as "sub foo;" or "sub foo($);". It does not include anonymous subroutines, as these are merely part of a normal statement.


"PPI::Statement::Sub" has a number of methods in addition to the standard PPI::Statement, PPI::Node and PPI::Element methods.


The "name" method returns the name of the subroutine being declared.

In some rare cases such as a naked "sub" at the end of the file, this may return false.


If it has one, the "prototype" method returns the subroutine's prototype. It is returned in the same format as ``prototype'' in PPI::Token::Prototype, cleaned and removed from its brackets.

Returns the subroutine's prototype, or undef if the subroutine does not define one. Note that when the sub has an empty prototype ("()") the return is an empty string.


With its name and implementation shared with PPI::Statement::Scheduled, the "block" method finds and returns the actual Structure object of the code block for this subroutine.

Returns false if this is a forward declaration, or otherwise does not have a code block.


The "forward" method returns true if the subroutine declaration is a forward declaration.

That is, it returns false if the subroutine has a code block, or true if it does not.


The "reserved" method provides a convenience method for checking to see if this is a special reserved subroutine. It does not check against any particular list of reserved sub names, but just returns true if the name is all uppercase, as defined in perlsub.

Note that in the case of BEGIN, CHECK, UNITCHECK, INIT and END, these will be defined as PPI::Statement::Scheduled objects, not subroutines.

Returns true if it is a special reserved subroutine, or false if not.


- Write unit tests for this package


See the support section in the main module.


Adam Kennedy <[email protected]>


Copyright 2001 - 2011 Adam Kennedy.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.