use Template::Document; $doc = Template::Document->new({ BLOCK => sub { # some perl code; return $some_text }, DEFBLOCKS => { header => sub { # more perl code; return $some_text }, footer => sub { # blah blah blah; return $some_text }, }, METADATA => { author => 'Andy Wardley', version => 3.14, } }) || die $Template::Document::ERROR; print $doc->process($context);
This module defines an object class whose instances represent compiled
template documents. The Template::Parser module creates a
Template::Document
instance to encapsulate a template as it
is compiled into Perl code.
The constructor method, new(), expects a
reference to a hash array containing the BLOCK
,
DEFBLOCKS
and METADATA
items.
The BLOCK
item should contain a reference to a Perl
subroutine or a textual representation of Perl code, as generated by the
Template::Parser
module. This is then evaluated into a subroutine reference using
eval()
.
The DEFLOCKS
item should reference a hash array containing
further named BLOCK
s which may be defined in the template.
The keys represent BLOCK
names and the values should be
subroutine references or text strings of Perl code as per the main
BLOCK
item.
The METADATA
item should reference a hash array of metadata
items relevant to the document.
The process() method can then be called on
the instantiated Template::Document
object, passing a
reference to a Template::Context object as the first parameter. This will
install any locally defined blocks (DEFBLOCKS
) in the
BLOCKS
cache in the context (via a call to visit()) so that
they may be subsequently resolved by the context. The main
BLOCK
subroutine is then executed, passing the context
reference on as a parameter. The text returned from the template
subroutine is then returned by the process() method, after calling the context leave()
method to permit cleanup and de-registration of named BLOCKS
previously installed.
An AUTOLOAD
method provides access to the
METADATA
items for the document. The Template::Service module installs
a reference to the main Template::Document
object in the
stash as the template
variable. This allows metadata items
to be accessed from within templates, including PRE_PROCESS
templates.
header:
<html>
<head>
<title>[% template.title %]
</head>
...
Template::Document
objects are usually created by the Template::Parser but can
be manually instantiated or sub-classed to provide custom template
components.
Constructor method which accept a reference to a hash array containing the structure as shown in this example:
$doc = Template::Document->new({ BLOCK => sub { # some perl code; return $some_text }, DEFBLOCKS => { header => sub { # more perl code; return $some_text }, footer => sub { # blah blah blah; return $some_text }, }, METADATA => { author => 'Andy Wardley', version => 3.14, } }) || die $Template::Document::ERROR;
BLOCK
and DEFBLOCKS
items may be expressed as
references to Perl subroutines or as text strings containing Perl
subroutine definitions, as is generated by the Template::Parser module. These are
evaluated into subroutine references using eval()
.
Returns a new Template::Document
object or
undef
on error. The error() class method can be called, or the
$ERROR
package variable inspected to retrieve the relevant
error message.
Main processing routine for the compiled template document. A reference to a Template::Context object should be passed as the first parameter. The method installs any locally defined blocks via a call to the context visit() method, processes its own template, (passing the context reference as a parameter) and then calls leave() in the context to allow cleanup.
print $doc->process($context);
Returns a text string representing the generated output for the template.
Errors are thrown via die()
.
Returns a reference to the main BLOCK
subroutine.
Returns a reference to the hash array of named DEFBLOCKS
subroutines.
Returns a reference to a hash of variables used in the template. This requires the TRACE_VARS option to be enabled.
An autoload method returns METADATA
items.
print $doc->author();
These methods are used internally.
This method generate a Perl representation of the template.
my $perl = Template::Document->as_perl({ BLOCK => $main_block, DEFBLOCKS => { foo => $foo_block, bar => $bar_block, }, METADATA => { name => 'my_template', } });
This method is used to write compiled Perl templates to disk. If the
COMPILE_EXT
option (to indicate a file extension for saving
compiled templates) then the Template::Parser module calls this subroutine before calling the
new() constructor. At this stage, the parser
has a representation of the template as text strings containing Perl
code. We can write that to a file, enclosed in a small wrapper which will
allow us to susequently require()
the file and have Perl
parse and compile it into a Template::Document
. Thus we have
persistence of compiled templates.
This is a simple handler used to catch any errors that arise when the compiled Perl template is first evaluated (that is, evaluated by Perl to create a template subroutine at compile, rather than the template being processed at runtime).
This is mapped to utf8::is_utf8
for versions of Perl that
have it (> 5.008) or to Encode::is_utf8
for Perl 5.008.
Earlier versions of Perl are not supported.
Andy Wardley <abw@wardley.org> https://wardley.org/
Copyright (C) 1996-2012 Andy Wardley. All Rights Reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.