NAME
Text::ScriptTemplate - Lightweight processor for full-featured templateSYNOPSIS
use Text::ScriptTemplate;
$tmpl = new Text::ScriptTemplate; # create processor object
$tmpl->setq(TEXT => "hello, world"); # export data to template
$tmpl->load($file); # loads template from named file
$tmpl->pack(q{TEXT: <%= $TEXT; %>}); # loads template from in-memory data
print $tmpl->fill; # prints "TEXT: hello, world"
# load intermixed Perl script and text as a template
$tmpl->pack(q{<% for (1..3) { %>i = <%= "$_\n"; %><% } %>});
print $tmpl->fill; # prints "i = 1\ni = 2\ni = 3\n"DESCRIPTION
This is a varient of Text::SimpleTemplate, a module for template-based text generation.
Template-based text generation is a way to separate program code and data, so non-programmer can control final result (like HTML) as desired without tweaking the program code itself. By doing so, jobs like website maintenance is much easier because you can leave program code unchanged even if page redesign was needed.
The idea of this module is simple. Whenever a block of text surrounded by '<%' and '%>' (or any pair of delimiters you specify) is found, it will be taken as Perl expression, and will be handled specially by template processing engine. With this module, Perl script and text can be intermixed closely.
Major goal of this library is to provide support of powerful PHP-style template with smaller resource. This is useful when PHP, HTML::Embperl, or Apache::ASP is overkill, but their template style is still desired.
INSTALLATION / REQUIREMENTS
This module requires Carp.pm and FileHandle.pm. Since these are standard modules, all you need is perl itself.
For installation, standard procedure of
perl Makefile.PL
make
make test
make installshould work just fine.
TEMPLATE SYNTAX AND USAGE
Any block of text surrounded by '<%' and '%>' will be handled specially by template processor.
For block surrounded by '<%=' and '%>, it will be taken as simple perl expression, and will be replace by its evaluated result.
For block surrounded by '<%' and '%>, it will be taken as part of control structure, and after all parts are merged into one big block, it will be evaluated and the result will be handled as output.
Suppose you have a following template named "sample.tmpl":
=== Module Information ===
<% if ($HAS->{Text::ScriptTemplate}) { %>
Name: <%= $INFO->{Name}; %>
Description: <%= $INFO->{Description}; %>
Author: <%= $INFO->{Author}; %> <<%= $INFO->{Email}; %>>
<% } else { %>
Text::ScriptTemplate is not installed.
<% } %>With the following code...
use Safe;
use Text::ScriptTemplate;
$tmpl = new Text::ScriptTemplate;
$tmpl->setq(INFO => {
Name => "Text::ScriptTemplate",
Description => "Lightweight processor for full-featured template",
Author => "Taisuke Yamada",
Email => "tai\@imasy.or.jp",
});
$tmpl->setq(HAS => { Text::ScriptTemplate => 1 }); # installed
$tmpl->load("sample.tmpl");
print $tmpl->fill(PACKAGE => new Safe);...you will get following result:
=== Module Information ===
Name: Text::ScriptTemplate
Description: Lightweight processor for full-featured template
Author: Taisuke Yamada <tai@imasy.or.jp>If you change
$tmpl->setq(HAS => { Text::ScriptTemplate => 1 }); # installedto
$tmpl->setq(HAS => { Text::ScriptTemplate => 0 }); # not installedthen you will get
=== Module Information ===
Text::ScriptTemplate is not installed.You can embed any control strucure as long as intermixed text block is surround by set of braces. This means
hello world<% if ($firsttime); %>must be written as
<% do { %>hello world<% } if ($firsttime); %>If you want to know more on this, please read TEMPLATE INTERNAL section for the detail.
Also, as you might have noticed, any scalar data can be exported to template namespace, even hash reference or code reference.
Finally, although I used "Safe" module in example above, this is not a requirement. However, if you want to control power of the template editor over program logic, its use is strongly recommended (see the Safe manpage for more).
RESERVED NAMES
Since template can be evaluated in separate namespace, this module does not have much restriction on variable or function name you define in theory.
However, due to internal structure of this module, please consider all names starting with "_" (underscore) as reserved for internal usage.
METHODS
Following methods are currently available.
- $tmpl = new Text::ScriptTemplate;
-
Constructor. Returns newly created object.
If this method was called through existing object, cloned object will be returned. This cloned instance inherits all properties except for internal buffer which holds template data. Cloning is useful for chained template processing.
- $tmpl->setq($name => $data, $name => $data, ...);
-
Exports scalar data ($data) to template namespace, with $name as a scalar variable name to be used in template.
You can repeat the pair to export multiple sets in one operation.
- $tmpl->load($file, %opts);
-
Loads template file ($file) for later evaluation. File can be specified in either form of pathname or fileglob.
This method accepts DELIM option, used to specify delimiter for parsing template. It is speficied by passing reference to array containing delimiter pair, just like below:
$tmpl->load($file, DELIM => [qw(<? ?>)]);Returns object reference to itself.
- $tmpl->pack($data, %opts);
-
Loads in-memory data ($data) for later evaluation. Except for this difference, works just like $tmpl->load.
- $text = $tmpl->fill(%opts);
-
Returns evaluated result of template, which was preloaded by either $tmpl->pack or $tmpl->load method.
This method accepts two options: PACKAGE and OHANDLE.
PACKAGE option specifies the namespace where template evaluation takes place. You can either pass the name of the package, or the package object itself. So either of
$tmpl->fill(PACKAGE => new Safe); $tmpl->fill(PACKAGE => new Some::Module); $tmpl->fill(PACKAGE => 'Some::Package');works. In case Safe module (or its subclass) was passed, its "reval" method will be used instead of built-in eval.
OHANDLE option is for output selection. By default, this method returns the result of evaluation, but with OHANDLE option set, you can instead make it print to given handle. Either style of
$tmpl->fill(OHANDLE => \*STDOUT); $tmpl->fill(OHANDLE => new FileHandle(...));is supported.
TEMPLATE INTERNAL
Internally, template processor converts template into one big perl script, and then simply executes it. Conversion rule is fairly simple - If you have following template,
<% if ($bool) { %>
hello, <%= $name; %>
<% } %>it will be converted into
if ($bool) {
$_handle->(q{
hello, });
$_handle->(do{ $name; });
$_handle->(q{
});
}Note line breaks are preserved. After all conversion is done, it will be executed. And depending on existance of OHANDLE option, $_handle (this is a code reference to predefined function) will either print or buffer its argument.
NOTES / BUGS
Nested template delimiter will cause this module to fail.
SEE ALSO
CONTACT ADDRESS
Please send any bug reports/comments to <tai@imasy.or.jp>.
AUTHORS / CONTRIBUTORS
- Taisuke Yamada <tai@imasy.or.jp>COPYRIGHT
Copyright 2001. All rights reserved.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.