PPI::Statement - The base class for Perl statements


PPI::Statement - The base class for Perl statements


  isa PPI::Node
      isa PPI::Element


PPI::Statement is the root class for all Perl statements. This includes (from the perlsyn manpage) ``Declarations'', ``Simple Statements'' and ``Compound Statements''.

The class PPI::Statement itself represents a ``Simple Statement'' as defined in the the perlsyn manpage manpage.


Please note that unless documented themselves, these classes are yet to be frozen/finalised. Names may change slightly or be added or removed.

the PPI::Statement::Scheduled manpage

This covers all ``scheduled'' blocks, chunks of code that are executed separately from the main body of the code, at a particular time. This includes all BEGIN, CHECK, INIT and END blocks.

the PPI::Statement::Package manpage

A package declaration, as defined in perlfunc.

the PPI::Statement::Include manpage

A statement that loads or unloads another module.

This includes 'use', 'no', and 'require' statements.

the PPI::Statement::Sub manpage

A named subroutine declaration, or forward declaration

the PPI::Statement::Variable manpage

A variable declaration statement. This could be either a straight declaration or also be an expression.

This includes all 'my', 'local' and 'out' statements.

the PPI::Statement::Compound manpage

This covers the whole family of 'compound' statements, as described in perlsyn.

This includes all statements starting with 'if', 'unless', 'for', 'foreach' and 'while'. Note that this does NOT include 'do', as it is treated differently.

All compound statements have implicit ends. That is, they do not end with a ';' statement terminator.

the PPI::Statement::Break manpage

A statement that breaks out of a structure.

This includes all of 'redo', 'next', 'last' and 'return' statements.

the PPI::Statement::Data manpage

A special statement which encompasses an entire __DATA__ block, including the initial '__DATA__' token itself and the entire contents.

the PPI::Statement::End manpage

A special statement which encompasses an entire __END__ block, including the initial '__END__' token itself and the entire contents, including any parsed PPI::Token::POD that may occur in it.

the PPI::Statement::Expression manpage

the PPI::Statement::Expression manpage is a little more speculative, and is intended to help represent the special rules relating to ``expressions'' such as in:

  # Several examples of expression statements
  # Boolean conditions
  if ( expression ) { ... }
  # Lists, such as for arguments
  Foo->bar( expression )

the PPI::Statement::Null manpage

A null statement is a special case for where we encounter two consecutive statement terminators. ( ;; )

The second terminator is given an entire statement of its own, but one that serves no purpose. Hence a 'null' statement.

Theoretically, assuming a correct parsing of a perl file, all null statements are superfluous and should be able to be removed without damage to the file.

But don't do that, in case PPI has parsed something wrong.

the PPI::Statement::UnmatchedBrace manpage

Because PPI is intended for use when parsing incorrect or incomplete code, the problem arises of what to do with a stray closing brace.

Rather than die, it is allocated its own ``unmatched brace'' statement, which really means ``unmatched closing brace''. An unmatched open brace at the end of a file would become a structure with no contents and no closing brace.

If the document loaded is intended to be correct and valid, finding a the PPI::Statement::UnmatchedBrace manpage in the PDOM is generally indicative of a misparse.

the PPI::Statement::Unknown manpage

This is used temporarily mid-parsing to hold statements for which the lexer cannot yet determine what class it should be, usually because there are insufficient clues, or it might be more than one thing.

You should never encounter these in a fully parsed PDOM tree.


PPI::Statement itself has very few methods. Most of the time, you will be working with the more generic the PPI::Element manpage or the PPI::Node manpage methods, or one of the methods that are subclass-specific.


One factor common to most statements is their ability to be labeled.

The label method returns the label for a statement, if one has been defined, but without the trailing colon. Take the following example

  MYLABEL: while ( 1 .. 10 ) { last MYLABEL if $_ > 5 }

For the above statement, the label method would return 'MYLABEL'.

Returns false if the statement does not have a label.


Much like the the PPI::Document manpage method of the same name, the ->stable method converts a statement to source and back again, to determine if a modified statement is still legal, and won't be interpreted in a different way.

Returns true if the statement is stable, false if not, or undef on error.


- Complete, freeze and document the remaining classes


See the support section in the main module.


Adam Kennedy <adamk@cpan.org>


Copyright 2001 - 2006 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.

 PPI::Statement - The base class for Perl statements