1Text::Xslate(3) User Contributed Perl Documentation Text::Xslate(3)
2
6 Text::Xslate - Scalable template engine for Perl5
7
9 This document describes Text::Xslate version v3.5.8.
10
12 use Text::Xslate qw(mark_raw);
13 my $tx = Text::Xslate->new();
15 my %vars = (
17 title => 'A list of books',
18 books => [
19 { title => 'Islands in the stream' },
20 { title => 'Programming Perl' },
21 # ...
22 ],
23 # mark HTML components as raw not to escape its HTML tags
25 gadget => mark_raw('<div class="gadget">...</div>'),
26 );
27 # for files
29 print $tx->render('hello.tx', \%vars);
30 # for strings (easy but slow)
32 my $template = q{
33 <h1><: $title :></h1>
34 <ul>
35 : for $books -> $book {
36 <li><: $book.title :></li>
37 : } # for
38 </ul>
39 };
40 print $tx->render_string($template, \%vars);
42
44 Xslate is a template engine, tuned for persistent applications, safe as
45 an HTML generator, and with rich features.
46 There are a lot of template engines in CPAN, for example Template-
48 Toolkit, Text::MicroTemplate, HTML::Template, and so on, but all of
49 them have some weak points: a full-featured template engine may be
50 slow, while a fast template engine may be too simple to use. This is
51 why Xslate is developed, which is the best template engine for web
52 applications.
53 The concept of Xslate is strongly influenced by Text::MicroTemplate and
55 Template-Toolkit 2, but the central philosophy of Xslate is different
56 from them. That is, the philosophy is sandboxing that the template
57 logic should not have no access outside the template beyond your
58 permission.
59 Other remarkable features are as follows:
61 Features
63 High performance
64 This engine introduces the virtual machine paradigm. Templates are
66 compiled into intermediate code, and then executed by the virtual
67 machine, which is highly optimized for rendering templates. Thus,
68 Xslate is much faster than any other template engines.
69 The template roundup project by Sam Graham shows Text::Xslate got
71 amazingly high scores in instance_reuse condition (i.e. for persistent
72 applications).
73 The template roundup project
75 <http://illusori.co.uk/projects/Template-Roundup/>
76 Perl Template Roundup October 2010 Performance vs Variant Report:
78 instance_reuse
79 <http://illusori.co.uk/projects/Template-Roundup/201010/performance_vs_variant_by_feature_for_instance_reuse.html>
80 There are also benchmarks in benchmark/ directory in the Xslate
82 distribution.
83 Smart escaping for HTML metacharacters
85 Xslate employs the smart escaping strategy, where a template engine
87 escapes all the HTML metacharacters in template expressions unless
88 users mark values as raw. That is, the output is unlikely to prone to
89 XSS.
90 Template cascading
92 Xslate supports the template cascading, which allows you to extend
94 templates with block modifiers. It is like a traditional template
95 inclusion, but is more powerful.
96 This mechanism is also called as template inheritance.
98 Easiness to enhance
100 Xslate is ready to enhance. You can add functions and methods to the
102 template engine and even add a new syntax via extending the parser.
103
105 Methods
106 Text::Xslate->new(%options)
107 Creates a new Xslate template engine with options. You can reuse this
109 instance for multiple calls to "render()".
110 Possible options are:
112 "path => \@path // ['.']"
114 Specifies the include paths, which may be directory names or
115 virtual paths, i.e. HASH references which contain "$file_name =>
116 $content" pairs.
117 Note that if you use taint mode ("-T"), you have to give absolute
119 paths to "path" and "cache_dir". Otherwise you'll get errors
120 because they depend on the current working directory which might
121 not be secure.
122 "cache => $level // 1"
124 Sets the cache level.
125 If "$level == 1" (default), Xslate caches compiled templates on the
127 disk, and checks the freshness of the original templates every
128 time.
129 If "$level >= 2", caches will be created but the freshness will not
131 be checked.
132 "$level == 0" uses no caches, which is provided for testing.
134 "cache_dir => $dir // "$ENV{HOME}/.xslate_cache""
136 Specifies the directory used for caches. If $ENV{HOME} doesn't
137 exist, "File::Spec->tmpdir" will be used.
138 You should specify this option for productions to avoid conflicts
140 of template names.
141 "function => \%functions"
143 Specifies a function map which contains name-coderef pairs. A
144 function "f" may be called as "f($arg)" or "$arg | f" in templates.
145 Note that these registered functions have to return a text string,
147 not a binary string unless you want to handle bytes in whole
148 templates. Make sure what you want to use returns either a text
149 string or a binary string.
150 For example, some methods of "Time::Piece" might return a binary
152 string which is encoded in UTF-8, so you'll want to decode their
153 values.
154 # under LANG=ja_JP.UTF-8 on MacOSX (Darwin 11.2.0)
156 use Time::Piece;
157 use Encode qw(decode);
158 sub ctime {
160 my $ctime = Time::Piece->new->strftime; # UTF-8 encoded bytes
161 return decode "UTF-8", $ctime;
162 }
163 my $tx = Text::Xslate->new(
165 function => {
166 ctime => \&ctime,
167 },
168 ...,
169 );
170 Built-in functions are described in Text::Xslate::Manual::Builtin.
172 "module => [$module => ?\@import_args, ...]"
174 Imports functions from $module, which may be a function-based or
175 bridge module. Optional @import_args are passed to "import" as
176 "$module->import(@import_args)".
177 For example:
179 # for function-based modules
181 my $tx = Text::Xslate->new(
182 module => ['Digest::SHA1' => [qw(sha1_hex)]],
183 );
184 print $tx->render_string(
185 '<: sha1_hex($x).substr(0, 6) :>',
186 { x => foo() },
187 ); # => 0beec7
188 # for bridge modules
190 my $tx = Text::Xslate->new(
191 module => ['Text::Xslate::Bridge::Star'],
192 );
193 print $tx->render_string(
194 '<: $x.uc() :>',
195 { x => 'foo' },
196 ); # => 'FOO'
197 Because you can use function-based modules with the "module"
199 option, and also can invoke any object methods in templates, Xslate
200 doesn't require specific namespaces for plugins.
201 "html_builder_module => [$module => ?\@import_args, ...]"
203 Imports functions from $module, wrapping each function with
204 "html_builder()".
205 "input_layer => $perliolayers // ':utf8'"
207 Specifies PerlIO layers to open template files.
208 "verbose => $level // 1"
210 Specifies the verbose level.
211 If "$level == 0", all the possible errors will be ignored.
213 If "$level >= 1" (default), trivial errors (e.g. to print nil) will
215 be ignored, but severe errors (e.g. for a method to throw the
216 error) will be warned.
217 If "$level >= 2", all the possible errors will be warned.
219 "suffix => $ext // '.tx'"
221 Specify the template suffix, which is used for "cascade" and
222 "include" in Kolon.
223 Note that this is used for static name resolution. That is, the
225 compiler uses it but the runtime engine doesn't.
226 "syntax => $name // 'Kolon'"
228 Specifies the template syntax you want to use.
229 $name may be a short name (e.g. "Kolon"), or a fully qualified name
231 (e.g. "Text::Xslate::Syntax::Kolon").
232 This option is passed to the compiler directly.
234 "type => $type // 'html'"
236 Specifies the output content type. If $type is "html" or "xml",
237 smart escaping is applied to template expressions. That is, they
238 are interpolated via the "html_escape" filter. If $type is "text"
239 smart escaping is not applied so that it is suitable for plain
240 texts like e-mails.
241 $type may be html, xml (identical to "html"), and text.
243 This option is passed to the compiler directly.
245 "line_start => $token // $parser_defined_str"
247 Specify the token to start line code as a string, which "quotemeta"
248 will be applied to. If you give "undef", the line code style is
249 disabled.
250 This option is passed to the parser via the compiler.
252 "tag_start => $str // $parser_defined_str"
254 Specify the token to start inline code as a string, which
255 "quotemeta" will be applied to.
256 This option is passed to the parser via the compiler.
258 "tag_end => $str // $parser_defined_str"
260 Specify the token to end inline code as a string, which "quotemeta"
261 will be applied to.
262 This option is passed to the parser via the compiler.
264 "header => \@template_files"
266 Specify the header template files, which are inserted to the head
267 of each template.
268 This option is passed to the compiler.
270 "footer => \@template_files"
272 Specify the footer template files, which are inserted to the foot
273 of each template.
274 This option is passed to the compiler.
276 "warn_handler => \&cb"
278 Specify the callback &cb which is called on warnings.
279 "die_handler => \&cb"
281 Specify the callback &cb which is called on fatal errors.
282 "pre_process_handler => \&cb"
284 Specify the callback &cb which is called after templates are loaded
285 from the disk in order to pre-process template.
286 For example:
288 # Remove whitespace from templates
290 my $tx = Text::Xslate->new(
291 pre_process_handler => sub {
292 my $text = shift;
293 $text=~s/\s+//g;
294 return $text;
295 }
296 );
297 The first argument is the template text string, which can be both
299 text strings and "byte strings".
300 This filter is applied only to files, not a string template for
302 "render_string".
303 $tx->render($file, \%vars) :Str
305 Renders a template file with given variables, and returns the result.
307 \%vars is optional.
308 Note that $file may be cached according to the cache level.
310 $tx->render_string($string, \%vars) :Str
312 Renders a template string with given variables, and returns the result.
314 \%vars is optional.
315 Note that $string is never cached, so this method should be avoided in
317 production environment. If you want in-memory templates, consider the
318 path option for HASH references which are cached as you expect:
319 my %vpath = (
321 'hello.tx' => 'Hello, <: $lang :> world!',
322 );
323 my $tx = Text::Xslate->new( path => \%vpath );
325 print $tx->render('hello.tx', { lang => 'Xslate' });
326 Note that $string must be a text string, not a binary string.
328 $tx->load_file($file) :Void
330 Loads $file into memory for following "render()". Compiles and saves
332 it as disk caches if needed.
333 Text::Xslate->current_engine :XslateEngine
335 Returns the current Xslate engine while executing. Otherwise returns
337 "undef". This method is significant when it is called by template
338 functions and methods.
339 Text::Xslate->current_vars :HashRef
341 Returns the current variable table, namely the second argument of
343 "render()" while executing. Otherwise returns "undef".
344 Text::Xslate->current_file :Str
346 Returns the current file name while executing. Otherwise returns
348 "undef". This method is significant when it is called by template
349 functions and methods.
350 Text::Xslate->current_line :Int
352 Returns the current line number while executing. Otherwise returns
354 "undef". This method is significant when it is called by template
355 functions and methods.
356 Text::Xslate->print(...) :Void
358 Adds the argument into the output buffer. This method is available on
360 executing.
361 $tx->validate($file) :Void
363 Checks whether the syntax of $file is valid or invalid as Xslate. If
365 it detects the invalid factor, this method throws the exception.
366 Exportable functions
368 "mark_raw($str :Str) :RawStr"
369 Marks $str as raw, so that the content of $str will be rendered as is,
371 so you have to escape these strings by yourself.
372 For example:
374 use Text::Xslate qw( mark_raw );
376 my $tx = Text::Xslate->new();
378 my $tmpl = 'Mailaddress: <: $email :>';
379 my %vars = (
380 email => mark_raw('Foo <foo at example.com>'),
381 );
382 print $tx->render_string($tmpl, \%email);
383 # => Mailaddress: Foo <foo@example.com>
384 This function is available in templates as the "mark_raw" filter,
386 although the use of it is strongly discouraged.
387 "unmark_raw($str :Str) :Str"
389 Clears the raw marker from $str, so that the content of $str will be
391 escaped before rendered.
392 This function is available in templates as the "unmark_raw" filter.
394 "html_escape($str :Str) :RawStr"
396 Escapes HTML meta characters in $str, and returns it as a raw string
398 (see above). If $str is already a raw string, it returns $str as is.
399 By default, this function will automatically be applied to all template
401 expressions.
402 This function is available in templates as the "html" filter, but
404 you're better off using "unmark_raw" to ensure that expressions are
405 html-escaped.
406 "uri_escape($str :Str) :Str"
408 Escapes URI unsafe characters in $str, and returns it.
410 This function is available in templates as the "uri" filter.
412 "html_builder { block } | \&function :CodeRef"
414 Wraps a block or &function with "mark_raw" so that the new subroutine
416 will return a raw string.
417 This function is used to tell the xslate engine that &function is an
419 HTML builder that returns HTML sources. For example:
420 sub some_html_builder {
422 my @args = @_;
423 my $html;
424 # build HTML ...
425 return $html;
426 }
427 my $tx = Text::Xslate->new(
429 function => {
430 some_html_builder => html_builder(\&some_html_builder),
431 },
432 );
433 See also Text::Xslate::Manual::Cookbook.
435 Command line interface
437 The xslate(1) command is provided as a CLI to the Text::Xslate module,
438 which is used to process directory trees or to evaluate one liners.
439 For example:
440 $ xslate -Dname=value -o dest_path src_path
442 $ xslate -e 'Hello, <: $ARGV[0] :> wolrd!' Xslate
444 $ xslate -s TTerse -e 'Hello, [% ARGV.0 %] world!' TTerse
445 See xslate(1) for details.
447
449 There are multiple template syntaxes available in Xslate.
450 Kolon
452 Kolon is the default syntax, using "<: ... :>" inline code and ":
453 ..." line code, which is explained in Text::Xslate::Syntax::Kolon.
454 Metakolon
456 Metakolon is the same as Kolon except for using "[% ... %]" inline
457 code and "%% ..." line code, instead of "<: ... :>" and ": ...".
458 TTerse
460 TTerse is a syntax that is a subset of Template-Toolkit 2 (and
461 partially TT3), which is explained in Text::Xslate::Syntax::TTerse.
462 HTMLTemplate
464 There's HTML::Template compatible layers in CPAN.
465 Text::Xslate::Syntax::HTMLTemplate is a syntax for HTML::Template.
467 HTML::Template::Parser is a converter from HTML::Template to
469 Text::Xslate.
470
472 There are common notes in Xslate.
473 Nil/undef handling
475 Note that nil (i.e. "undef" in Perl) handling is different from Perl's.
476 Basically it does nothing, but "verbose => 2" will produce warnings on
477 it.
478 to print
480 Prints nothing.
481 to access fields
483 Returns nil. That is, "nil.foo.bar.baz" produces nil.
484 to invoke methods
486 Returns nil. That is, "nil.foo().bar().baz()" produces nil.
487 to iterate
489 Dealt as an empty array.
490 equality
492 "$var == nil" returns true if and only if $var is nil.
493
495 Perl 5.8.1 or later.
496 If you have a C compiler, the XS backend will be used. Otherwise the
498 pure Perl backend will be used.
499
501 • Context controls. e.g. "<: [ $foo->bar @list ] :>".
502 • Augment modifiers.
504 • Default arguments and named arguments for macros.
506 • External macros.
508 Just idea: in the new macro concept, macros and external templates
510 will be the same in internals:
511 : macro foo($lang) { "Hello, " ~ $lang ~ " world!" }
513 : include foo { lang => 'Xslate' }
514 : # => 'Hello, Xslate world!'
515 : extern bar 'my/bar.tx'; # 'extern bar $file' is ok
517 : bar( value => 42 ); # calls an external template
518 : include bar { value => 42 } # ditto
519 • A "too-safe" HTML escaping filter which escape all the symbolic
521 characters
522
524 PROJECT HOME: <https://github.com/xslate/>
525 REPOSITORY: <https://github.com/xslate/p5-Text-Xslate/>
527
529 Please report issues at
530 <https://github.com/xslate/p5-Text-Xslate/issues>. Patches are always
531 welcome.
532
534 Documents:
535 Text::Xslate::Manual
537 Xslate template syntaxes:
539 Text::Xslate::Syntax::Kolon
541 Text::Xslate::Syntax::Metakolon
543 Text::Xslate::Syntax::TTerse
545 Xslate command:
547 xslate
549 Other template modules that Xslate has been influenced by:
551 Text::MicroTemplate
553 Text::MicroTemplate::Extended
555 Text::ClearSilver
557 Template (Template::Toolkit)
559 HTML::Template
561 HTML::Template::Pro
563 Template::Alloy
565 Template::Sandbox
567 Benchmarks:
569 Template::Benchmark
571 Papers:
573 <http://www.cs.usfca.edu/~parrt/papers/mvc.templates.pdf> - Enforcing
575 Strict Model-View Separation in Template Engines
576
578 Thanks to lestrrat for the suggestion to the interface of "render()",
579 the contribution of Text::Xslate::Runner (was App::Xslate), and a lot
580 of suggestions.
581 Thanks to tokuhirom for the ideas, feature requests, encouragement, and
583 bug finding.
584 Thanks to gardejo for the proposal to the name template cascading.
586 Thanks to makamaka for the contribution of Text::Xslate::PP.
588 Thanks to jjn1056 to the concept of template overlay (now implemented
590 as "cascade with ...").
591 Thanks to typester for the various inspirations.
593 Thanks to clouder for the patch of adding "AND" and "OR" to TTerse.
595 Thanks to punytan for the documentation improvement.
597 Thanks to chiba for the bug reports and patches.
599 Thanks to turugina for the patch to fix Win32 problems
601 Thanks to Sam Graham for the bug reports.
603 Thanks to Mons Anderson for the bug reports and patches.
605 Thanks to hirose31 for the feature requests and bug reports.
607 Thanks to c9s for the contribution of the documents.
609 Thanks to shiba_yu36 for the bug reports.
611 Thanks to kane46taka for the bug reports.
613 Thanks to cho45 for the bug reports.
615 Thanks to shmorimo for the bug reports.
617 Thanks to ueda for the suggestions.
619
621 Fuji, Goro (gfx) <gfuji@cpan.org>.
622 Makamaka Hannyaharamitu (makamaka) (Text::Xslate::PP)
624 Maki, Daisuke (lestrrat) (Text::Xslate::Runner)
626
628 Copyright (c) 2010-2013, Fuji, Goro (gfx). All rights reserved.
629 This library is free software; you can redistribute it and/or modify it
631 under the same terms as Perl itself.
632perl v5.34.0 2021-07-23 Text::Xslate(3)