# # Copyright (C) 1998 Ken MacLeod # XML::Grove::Subst is free software; you can redistribute it # and/or modify it under the same terms as Perl itself. # # $Id: Subst.pm,v 1.3 1999/08/25 16:49:32 kmacleod Exp $ # use strict; package XML::Grove::Subst; sub new { my $class = shift; return bless {}, $class; } sub subst { my $self = shift; my $grove_fragment = shift; my $args = [ @_ ]; return ($grove_fragment->accept($self, $args)); } sub subst_hash { my $self = shift; my $grove_fragment = shift; my $args = shift; return ($grove_fragment->accept($self, $args)); } sub visit_document { my $self = shift; my $document = shift; my $contents = [ $document->children_accept ($self, @_) ]; return XML::Grove::Document->new( Contents => $contents ); } sub visit_element { my $self = shift; my $element = shift; my $name = $element->{Name}; if ($name eq 'SUB:key') { my $subst = $_[0]{$element->{Attributes}{'key'}}; if (ref($subst) eq 'ARRAY') { return @$subst; } else { if (ref($subst)) { return $subst; } else { return XML::Grove::Characters->new( Data => $subst ); } } } elsif ($name =~ /^SUB:(.*)$/) { my $subst = $_[0][$1 - 1]; if (ref($subst) eq 'ARRAY') { return @$subst; } else { if (ref($subst)) { return $subst; } else { return XML::Grove::Characters->new( Data => $subst ); } } } my $contents = [ $element->children_accept ($self, @_) ]; return XML::Grove::Element->new( Name => $name, Nttributes => $element->{Attributes}, Contents => $contents ); } sub visit_pi { my $self = shift; my $pi = shift; return $pi; } sub visit_characters { my $self = shift; my $characters = shift; return $characters; } ### ### Extend the XML::Grove::Document and XML::Grove::Element packages with our ### new function. ### package XML::Grove::Document; sub subst { my $self = shift; return (XML::Grove::Subst->new->subst($self, @_)); } sub subst_hash { my $self = shift; return (XML::Grove::Subst->new->subst_hash($self, @_)); } package XML::Grove::Element; sub subst { my $self = shift; return (XML::Grove::Subst->new->subst($self, @_)); } sub subst_hash { my $self = shift; return (XML::Grove::Subst->new->subst_hash($self, @_)); } 1; __END__ =head1 NAME XML::Grove::Subst - substitute values into a template =head1 SYNOPSIS use XML::Grove::Subst; # Using subst method on XML::Grove::Document or XML::Grove::Element: $new_grove = $source_grove->subst( ARGS ); $new_grove = $source_grove->subst_hash( ARG ); # Using an XML::Grove::Subst instance: $subster = XML::Grove::Subst->new(); $new_grove = $subster->subst( $source_grove, ARGS ); $new_grove = $subster->subst_hash( $source_grove, ARG ); =head1 DESCRIPTION C implements XML templates. C traverses through a source grove replacing all elements with names `C' or `C' with their corresponding values from ARGS (a list) or ARG (a hash), repsectively. =head1 METHODS =over 4 =item $grove_obj->subst( I ) =item $subster->subst( $grove_obj, I ) Search for `C>' elements, where I is an array index, and replace the element with the value from I, a list of values. The return value is a new grove with the substitutions applied. =item $grove_obj->subst_hash( I ) =item $subster->subst_hash( $grove_obj, I ) Search for `C' elements and replace the element with the value from I, a hash of values. The hash key is taken from the `C' attribute of the `C' element, for example, `CSUB:key key='foo'E>'. The return value is a new grove with the substitutions applied. =head1 EXAMPLE The following template, in a file `C', could be used for a simple parts database conversion to HTML: <SUB:key key='Name'>

Information for part number :
To use this template you would first parse it and convert it to a grove, and then use `C' every time you needed a new page: use XML::Parser::PerlSAX; use XML::Grove; use XML::Grove::Builder; use XML::Grove::Subst; use XML::Grove::PerlSAX; use XML::Handler::XMLWriter; # Load the template $b = XML::Grove::Builder->new(); $p = XML::Parser::PerlSAX->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->new(); $wp = XML::Grove::PerlSAX->new( Handler => $w ); $wp->parse( Source => { Grove => $new_grove } ); =head1 AUTHOR Ken MacLeod, ken@bitsko.slc.ut.us =head1 SEE ALSO perl(1), XML::Grove(3) Extensible Markup Language (XML) =cut