# phpman > perldoc > XML::Grove::Subst ## NAME [XML::Grove::Subst](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ASubst/markdown) - substitute values into a template ## SYNOPSIS use [XML::Grove::Subst](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ASubst/markdown); # Using subst method on [XML::Grove::Document](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ADocument/markdown) or [XML::Grove::Element](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3AElement/markdown): $new_grove = $source_grove->subst( ARGS ); $new_grove = $source_grove->subst_hash( ARG ); # Using an [XML::Grove::Subst](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ASubst/markdown) instance: $subster = [XML::Grove::Subst](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ASubst/markdown)->new(); $new_grove = $subster->subst( $source_grove, ARGS ); $new_grove = $subster->subst_hash( $source_grove, ARG ); ## DESCRIPTION "[XML::Grove::Subst](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ASubst/markdown)" implements XML templates. "[XML::Grove::Subst](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ASubst/markdown)" traverses through a source grove replacing all elements with names `"SUB:XXX"' or `"SUB:key"' with their corresponding values from ARGS (a list) or ARG (a hash), repsectively. ## METHODS $grove_obj->subst( *ARGS* ) =item $subster->subst( $grove_obj, *ARGS* ) Search for `"SUB:*XXX*"' elements, where *XXX* is an array index, and replace the element with the value from *ARGS*, a list of values. The return value is a new grove with the substitutions applied. $grove_obj->subst_hash( *ARG* ) =item $subster->subst_hash( $grove_obj, *ARG* ) Search for `"SUB:key"' elements and replace the element with the value from *ARG*, a hash of values. The hash key is taken from the `"key"' attribute of the `"SUB:key"' element, for example, `""'. The return value is a new grove with the substitutions applied. ## EXAMPLE The following template, in a file `"template.xml"', could be used for a simple parts database conversion to HTML: <SUB:key key='Name'>

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To use this template you would first parse it and convert it to a grove, and then use `"subst_hash()"' every time you needed a new page: use [XML::Parser::PerlSAX](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AParser%3A%3APerlSAX/markdown); use [XML::Grove](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove/markdown); use [XML::Grove::Builder](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ABuilder/markdown); use [XML::Grove::Subst](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ASubst/markdown); use [XML::Grove::PerlSAX](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3APerlSAX/markdown); use [XML::Handler::XMLWriter](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AHandler%3A%3AXMLWriter/markdown); # Load the template $b = [XML::Grove::Builder](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3ABuilder/markdown)->new(); $p = [XML::Parser::PerlSAX](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AParser%3A%3APerlSAX/markdown)->new( Handler = $b ); $source_grove = $p->parse( Source => { SystemId => 'template.xml' } ); # Apply the substitutions $new_grove = $source_grove->subst_hash( { Name => 'Acme DCX-2000 Filter', Number => 'N4728', Description => 'The Best' } ); # Write the new grove to standard output $w = [XML::Handler::XMLWriter](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AHandler%3A%3AXMLWriter/markdown)->new(); $wp = [XML::Grove::PerlSAX](https://www.chedong.com/phpMan.php/perldoc/XML%3A%3AGrove%3A%3APerlSAX/markdown)->new( Handler => $w ); $wp->parse( Source => { Grove => $new_grove } ); ## AUTHOR Ken MacLeod, ## SEE ALSO ### perl Extensible Markup Language (XML) <>