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<title>Summary of Perl 5 AST nodes</title>
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<p><a name="__index__"></a></p>
<!-- INDEX BEGIN -->
<ul>
<li><a href="#summary_of_perl_5_ast_nodes">Summary of Perl 5 AST nodes</a></li>
<ul>
<li><a href="#p5ast01__scope">P5AST01 - scope</a></li>
<ul>
<li><a href="#abstract">Abstract</a></li>
<li><a href="#elements">Elements</a></li>
<li><a href="#example">Example</a></li>
</ul>
<li><a href="#p5ast02__package">P5AST02 - package</a></li>
<ul>
<li><a href="#abstract">Abstract</a></li>
<li><a href="#elements">Elements</a></li>
<li><a href="#example">Example</a></li>
</ul>
<li><a href="#p5ast03__block">P5AST03 - block</a></li>
<ul>
<li><a href="#example">Example</a></li>
</ul>
<li><a href="#p5ast04__variable_declaration">P5AST04 - variable_declaration</a></li>
<ul>
<li><a href="#abstract">Abstract</a></li>
<li><a href="#elements">Elements</a></li>
</ul>
<li><a href="#p5ast05__scoped_variable_declaration">P5AST05 - scoped_variable_declaration</a></li>
<ul>
<li><a href="#abstract">Abstract</a></li>
<li><a href="#elements">Elements</a></li>
</ul>
<li><a href="#p5ast06__global_variable_declaration">P5AST06 - global_variable_declaration</a></li>
<ul>
<li><a href="#abstract">Abstract</a></li>
</ul>
</ul>
</ul>
<!-- INDEX END -->
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<p>
</p>
<h1><a name="summary_of_perl_5_ast_nodes">Summary of Perl 5 AST nodes</a></h1>
<p>
</p>
<h2><a name="p5ast01__scope">P5AST01 - scope</a></h2>
<p>
</p>
<h3><a name="abstract">Abstract</a></h3>
<p>The scope node is used for every new scope in the code. It delimits
the lifespan of variables and pragmas. If a pragma is defined a new
scope is open, if a variable is redeclared, a new scope is open. An
optimizer can reuse the scope for pragma declarations in the start of
the code. But it cannot rename the re-declared variable, as the stash
can be manipulated, just emit a warning.</p>
<p>
</p>
<h3><a name="elements">Elements</a></h3>
<dl>
<dt><strong><a name="item_scoped_declarations">scoped_declarations</a></strong><br />
</dt>
<dd>
a list of nodes containing scoped_variable_declaration, and
pragma_declaration. The list is ordered according to the source code.
</dd>
<p></p>
<dt><strong><a name="item_outer_references">outer_references</a></strong><br />
</dt>
<dd>
A list of nodes containing variables accessed by this scope that are
defined by the parent scope, or outer_referenced by the parent scope.
</dd>
<p></p>
<dt><strong><a name="item_children">children</a></strong><br />
</dt>
<dd>
A list of statements to be run inside this scope.
</dd>
<p></p></dl>
<p>
</p>
<h3><a name="example">Example</a></h3>
<pre>
block_decl
helloworld</pre>
<p>
</p>
<h2><a name="p5ast02__package">P5AST02 - package</a></h2>
<p>
</p>
<h3><a name="abstract">Abstract</a></h3>
<p>The package node is the root node of a Perl5 AST. It can declare
subroutines, global variables. It inherits the ``scope'' node as every
package defines a new scope.</p>
<p>
</p>
<h3><a name="elements">Elements</a></h3>
<dl>
<dt><strong><a name="item_name">name</a></strong><br />
</dt>
<dd>
The name of the package, default to 'main'.
</dd>
<p></p>
<dt><strong><a name="item_package_declarations">package_declarations</a></strong><br />
</dt>
<dd>
A list of nodes containing global_variable_declaration,
subroutine_declaration and use_declaration.
</dd>
<p></p></dl>
<p>
</p>
<h3><a name="example">Example</a></h3>
<pre>
block_decl
helloworld</pre>
<p>
</p>
<h2><a name="p5ast03__block">P5AST03 - block</a></h2>
<p>A block is a scope (inherits scope) defined explicitly. It tell us
that it is ok to redeclare a variable, and no warning is necessary.
It is also the boundary for closures.</p>
<p>
</p>
<h3><a name="example">Example</a></h3>
<pre>
block_decl</pre>
<p>
</p>
<h2><a name="p5ast04__variable_declaration">P5AST04 - variable_declaration</a></h2>
<p>
</p>
<h3><a name="abstract">Abstract</a></h3>
<p>The variable_declaration is the super-class for scoped and global
variable declaration. It defines how a variable can be declared.</p>
<p>
</p>
<h3><a name="elements">Elements</a></h3>
<dl>
<dt><strong><a name="item_variable_type">variable_type</a></strong><br />
</dt>
<dd>
One of SCALAR, ARRAY, HASH or GLOB. GLOBs can only be scoped with
local, and they're always global. Even if they're scoped.
</dd>
<p></p>
<dt><strong><a name="item_variable_name">variable_name</a></strong><br />
</dt>
<dd>
An expression that defines the name of the variable. This expression
should be evaluated every time the variable is used. It can reference
another variable in this expression. An outer_references entry should
be added if the referenced variable is from the parent scope.
</dd>
<p></p>
<dt><strong><a name="item_alias">alias</a></strong><br />
</dt>
<dd>
Alias to be used inside the AST when referencing this variable. For
optimizing performance, it should be unique in this AST.
</dd>
<p></p></dl>
<p>
</p>
<h2><a name="p5ast05__scoped_variable_declaration">P5AST05 - scoped_variable_declaration</a></h2>
<p>
</p>
<h3><a name="abstract">Abstract</a></h3>
<p>Defines a variable with a limited visibility, either by name or by
value. Inherits variable_declaration.</p>
<p>
</p>
<h3><a name="elements">Elements</a></h3>
<dl>
<dt><strong><a name="item_variable_visibility">variable_visibility</a></strong><br />
</dt>
<dd>
One of ``my'' or ``local''. If ``local'', it should also declare a ``global''
variable.
</dd>
<p></p></dl>
<p>
</p>
<h2><a name="p5ast06__global_variable_declaration">P5AST06 - global_variable_declaration</a></h2>
<p>
</p>
<h3><a name="abstract">Abstract</a></h3>
<p>This node causes the same effect of the ``our'' declaration, but appears
here even if the declaration didn't appears in the original code.</p>
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