blib/lib/Template/Declare.pm | |||
---|---|---|---|
Criterion | Covered | Total | % |
statement | 153 | 168 | 91.0 |
branch | 36 | 46 | 78.2 |
condition | 14 | 21 | 66.6 |
subroutine | 37 | 42 | 88.1 |
pod | 18 | 18 | 100.0 |
total | 258 | 295 | 87.4 |
line | stmt | bran | cond | sub | pod | time | code |
---|---|---|---|---|---|---|---|
1 | 48 | 48 | 74148 | use 5.006; | |||
48 | 139 | ||||||
48 | 1747 | ||||||
2 | 48 | 48 | 200 | use warnings; | |||
48 | 55 | ||||||
48 | 1201 | ||||||
3 | 48 | 48 | 194 | use strict; | |||
48 | 62 | ||||||
48 | 1776 | ||||||
4 | |||||||
5 | package Template::Declare; | ||||||
6 | 48 | 48 | 18932 | use Template::Declare::Buffer; | |||
48 | 143 | ||||||
48 | 1144 | ||||||
7 | 48 | 48 | 26713 | use Class::ISA; | |||
48 | 113119 | ||||||
48 | 1685 | ||||||
8 | 48 | 48 | 28241 | use String::BufferStack; | |||
48 | 78741 | ||||||
48 | 2471 | ||||||
9 | |||||||
10 | our $VERSION = '0.47'; | ||||||
11 | |||||||
12 | 48 | 48 | 354 | use base 'Class::Data::Inheritable'; | |||
48 | 81 | ||||||
48 | 30535 | ||||||
13 | __PACKAGE__->mk_classdata('dispatch_to'); | ||||||
14 | __PACKAGE__->mk_classdata('postprocessor'); | ||||||
15 | __PACKAGE__->mk_classdata('strict'); | ||||||
16 | __PACKAGE__->mk_classdata('templates'); | ||||||
17 | __PACKAGE__->mk_classdata('private_templates'); | ||||||
18 | __PACKAGE__->mk_classdata('buffer'); | ||||||
19 | __PACKAGE__->mk_classdata('imported_into'); | ||||||
20 | __PACKAGE__->mk_classdata('around_template'); | ||||||
21 | |||||||
22 | __PACKAGE__->dispatch_to( [] ); | ||||||
23 | __PACKAGE__->postprocessor( sub { return wantarray ? @_ : $_[0] } ); | ||||||
24 | __PACKAGE__->templates( {} ); | ||||||
25 | __PACKAGE__->private_templates( {} ); | ||||||
26 | __PACKAGE__->buffer( String::BufferStack->new ); | ||||||
27 | __PACKAGE__->around_template( undef ); | ||||||
28 | |||||||
29 | *String::BufferStack::data = sub { | ||||||
30 | 72 | 72 | 2119 | my $ref = shift; | |||
31 | 72 | 50 | 509 | if (@_) { | |||
32 | 0 | 0 | warn "Template::Declare->buffer->data called with argument; this usage is deprecated"; | ||||
33 | 0 | 0 | ${$ref->buffer_ref} = join("", @_); | ||||
0 | 0 | ||||||
34 | } | ||||||
35 | 72 | 305 | return $ref->buffer; | ||||
36 | }; | ||||||
37 | |||||||
38 | our $TEMPLATE_VARS; | ||||||
39 | |||||||
40 | =head1 NAME | ||||||
41 | |||||||
42 | Template::Declare - Perlish declarative templates | ||||||
43 | |||||||
44 | =head1 SYNOPSIS | ||||||
45 | |||||||
46 | Here's an example of basic HTML usage: | ||||||
47 | |||||||
48 | package MyApp::Templates; | ||||||
49 | use Template::Declare::Tags; # defaults to 'HTML' | ||||||
50 | use base 'Template::Declare'; | ||||||
51 | |||||||
52 | template simple => sub { | ||||||
53 | html { | ||||||
54 | head {} | ||||||
55 | body { | ||||||
56 | p { 'Hello, world wide web!' } | ||||||
57 | } | ||||||
58 | } | ||||||
59 | }; | ||||||
60 | |||||||
61 | package main; | ||||||
62 | use Template::Declare; | ||||||
63 | Template::Declare->init( dispatch_to => ['MyApp::Templates'] ); | ||||||
64 | print Template::Declare->show( 'simple' ); | ||||||
65 | |||||||
66 | And here's the output: | ||||||
67 | |||||||
68 | |||||||
69 | |||||||
70 | |||||||
71 | Hello, world wide web! |
||||||
72 | |||||||
73 | |||||||
74 | |||||||
75 | |||||||
76 | =head1 DESCRIPTION | ||||||
77 | |||||||
78 | C |
||||||
79 | system. | ||||||
80 | |||||||
81 | Yes. Another one. There are many others like it, but this one is ours. | ||||||
82 | |||||||
83 | A few key features and buzzwords: | ||||||
84 | |||||||
85 | =over | ||||||
86 | |||||||
87 | =item * | ||||||
88 | |||||||
89 | All templates are 100% pure Perl code | ||||||
90 | |||||||
91 | =item * | ||||||
92 | |||||||
93 | Simple declarative syntax | ||||||
94 | |||||||
95 | =item * | ||||||
96 | |||||||
97 | No angle brackets | ||||||
98 | |||||||
99 | =item * | ||||||
100 | |||||||
101 | "Native" XML namespace and declaration support | ||||||
102 | |||||||
103 | =item * | ||||||
104 | |||||||
105 | Mixins | ||||||
106 | |||||||
107 | =item * | ||||||
108 | |||||||
109 | Inheritance | ||||||
110 | |||||||
111 | =item * | ||||||
112 | |||||||
113 | Delegation | ||||||
114 | |||||||
115 | =item * | ||||||
116 | |||||||
117 | Public and private templates | ||||||
118 | |||||||
119 | =back | ||||||
120 | |||||||
121 | =head1 GLOSSARY | ||||||
122 | |||||||
123 | =over | ||||||
124 | |||||||
125 | =item template class | ||||||
126 | |||||||
127 | A subclass of Template::Declare in which one or more templates are defined | ||||||
128 | using the C keyword, or that inherits templates from a super class. | ||||||
129 | |||||||
130 | =item template | ||||||
131 | |||||||
132 | Created with the C keyword, a template is a subroutine that uses | ||||||
133 | C |
||||||
134 | |||||||
135 | =item attribute | ||||||
136 | |||||||
137 | An XML element attribute. For example, in C<< >>, C |
||||||
138 | is an attribute of the C element. | ||||||
139 | |||||||
140 | =item tag | ||||||
141 | |||||||
142 | A subroutine that generates XML element-style output. Tag subroutines execute | ||||||
143 | blocks that generate the output, and can call other tags to generate a | ||||||
144 | properly hierarchical structure. | ||||||
145 | |||||||
146 | =item tag set | ||||||
147 | |||||||
148 | A collection of related tags defined in a subclass of | ||||||
149 | L |
||||||
150 | imported into a template class. For example, | ||||||
151 | L |
||||||
152 | |||||||
153 | =item wrapper | ||||||
154 | |||||||
155 | A subroutine that wraps the output from a template. Useful for wrapping | ||||||
156 | template output in common headers and footers, for example. | ||||||
157 | |||||||
158 | =item dispatch class | ||||||
159 | |||||||
160 | A template class that has been passed to L |
||||||
161 | C |
||||||
162 | templates defined in or mixed into the dispatch classes will be executed. | ||||||
163 | |||||||
164 | =item path | ||||||
165 | |||||||
166 | The name specified for a template when it is created by the C | ||||||
167 | keyword, or when a template is mixed into a template class. | ||||||
168 | |||||||
169 | =item mixin | ||||||
170 | |||||||
171 | A template mixed into a template class via L. Mixed-in templates may be | ||||||
172 | mixed in under prefix paths to distinguish them from the templates defined in | ||||||
173 | the dispatch classes. | ||||||
174 | |||||||
175 | =item alias | ||||||
176 | |||||||
177 | A template aliased into a template class via L. Aliased templates may | ||||||
178 | be added under prefix paths to distinguish them from the templates defined in | ||||||
179 | the dispatch classes. | ||||||
180 | |||||||
181 | =item package variable | ||||||
182 | |||||||
183 | Variables defined when mixing templates into a template class. These variables | ||||||
184 | are available only to the mixed-in templates; they are not even accessible | ||||||
185 | from the template class in which the templates were defined. | ||||||
186 | |||||||
187 | =item helper | ||||||
188 | |||||||
189 | A subroutine used in templates to assist in the generation of output, or in | ||||||
190 | template classes to assist in the mixing-in of templates. Output helpers | ||||||
191 | include C |
||||||
192 | declarations. Mixin helpers include C |
||||||
193 | mix into, and C |
||||||
194 | templates. | ||||||
195 | |||||||
196 | =back | ||||||
197 | |||||||
198 | =head1 USAGE | ||||||
199 | |||||||
200 | Like other Perl templating systems, there are two parts to Template::Declare: | ||||||
201 | the templates and the code that loads and executes the templates. Unlike other | ||||||
202 | template systems, the templates are written in Perl classes. A simple HTML | ||||||
203 | example is in the L. | ||||||
204 | |||||||
205 | =head2 A slightly more advanced example | ||||||
206 | |||||||
207 | In this example, we'll show off how to set attributes on HTML tags, how to | ||||||
208 | call other templates, and how to declare a I |
||||||
209 | called directly. We'll also show passing arguments to templates. First, the | ||||||
210 | template class: | ||||||
211 | |||||||
212 | package MyApp::Templates; | ||||||
213 | use base 'Template::Declare'; | ||||||
214 | use Template::Declare::Tags; | ||||||
215 | |||||||
216 | private template 'util/header' => sub { | ||||||
217 | head { | ||||||
218 | title { 'This is a webpage' }; | ||||||
219 | meta { | ||||||
220 | attr { generator => "This is not your father's frontpage" } | ||||||
221 | } | ||||||
222 | } | ||||||
223 | }; | ||||||
224 | |||||||
225 | private template 'util/footer' => sub { | ||||||
226 | my $self = shift; | ||||||
227 | my $time = shift || gmtime; | ||||||
228 | |||||||
229 | div { | ||||||
230 | attr { id => "footer"}; | ||||||
231 | "Page last generated at $time." | ||||||
232 | } | ||||||
233 | }; | ||||||
234 | |||||||
235 | template simple => sub { | ||||||
236 | my $self = shift; | ||||||
237 | my $user = shift || 'world wide web'; | ||||||
238 | |||||||
239 | html { | ||||||
240 | show('util/header'); | ||||||
241 | body { | ||||||
242 | img { src is 'hello.jpg' } | ||||||
243 | p { | ||||||
244 | attr { class => 'greeting'}; | ||||||
245 | "Hello, $user!" | ||||||
246 | }; | ||||||
247 | }; | ||||||
248 | show('util/footer', 'noon'); | ||||||
249 | } | ||||||
250 | }; | ||||||
251 | |||||||
252 | A few notes on this example: | ||||||
253 | |||||||
254 | =over | ||||||
255 | |||||||
256 | =item * | ||||||
257 | |||||||
258 | Since no parameter was passed to C | ||||||
259 | are imported by default. | ||||||
260 | |||||||
261 | =item * | ||||||
262 | |||||||
263 | The C |
||||||
264 | it can only be executed by other templates within the template class in which | ||||||
265 | it's declared. By default, C<< Template::Declare->show >> will not dispatch to | ||||||
266 | it. | ||||||
267 | |||||||
268 | =item * | ||||||
269 | |||||||
270 | The two private templates have longer paths than we've seen before: | ||||||
271 | C |
||||||
272 | path names. You can put any characters you like into template names, but the | ||||||
273 | use of Unix filesystem-style paths is the most common (following on the | ||||||
274 | example of L |
||||||
275 | |||||||
276 | =item * | ||||||
277 | |||||||
278 | The first argument to a template is a class name. This can be useful for | ||||||
279 | calling methods defined in the class. | ||||||
280 | |||||||
281 | =item * | ||||||
282 | |||||||
283 | The C |
||||||
284 | template calls C |
||||||
285 | execute those private templates in the appropriate places. | ||||||
286 | |||||||
287 | =item * | ||||||
288 | |||||||
289 | Additional arguments to C |
||||||
290 | Here, C |
||||||
291 | template, with the result that the "last generated at" string will display | ||||||
292 | "noon" instead of the default C |
||||||
293 | |||||||
294 | =item * | ||||||
295 | |||||||
296 | In the same way, note that the C |
||||||
297 | argument, a user name. | ||||||
298 | |||||||
299 | =item * | ||||||
300 | |||||||
301 | In addition to using C |
||||||
302 | use C |
||||||
303 | |||||||
304 | img { src is 'hello.jpg' } | ||||||
305 | |||||||
306 | =back | ||||||
307 | |||||||
308 | Now for executing the template: | ||||||
309 | |||||||
310 | package main; | ||||||
311 | use Template::Declare; | ||||||
312 | Template::Declare->init( dispatch_to => ['MyApp::Templates'] ); | ||||||
313 | print Template::Declare->show( '/simple', 'TD user'); | ||||||
314 | |||||||
315 | We've told Template::Declare to dispatch to templates defined in our template | ||||||
316 | class. And note how an additional argument is passed to C |
||||||
317 | argument, "TD user", will be passed to the C |
||||||
318 | be used in the C<$user> variable. | ||||||
319 | |||||||
320 | The output looks like this: | ||||||
321 | |||||||
322 | |||||||
323 | |||||||
324 | |
||||||
325 | |||||||
326 | |||||||
327 | |||||||
328 | |||||||
329 | Hello, TD user! |
||||||
330 | |||||||
331 | |||||||
332 | |||||||
333 | |||||||
334 | Note that the single quote in C |
||||||
335 | your output for you to help prevent cross-site scripting attacks. | ||||||
336 | |||||||
337 | =head2 XUL | ||||||
338 | |||||||
339 | Template::Declare isn't limited to just HTML. Let's do XUL! | ||||||
340 | |||||||
341 | package MyApp::Templates; | ||||||
342 | use base 'Template::Declare'; | ||||||
343 | use Template::Declare::Tags 'XUL'; | ||||||
344 | |||||||
345 | template main => sub { | ||||||
346 | xml_decl { 'xml', version => '1.0' }; | ||||||
347 | xml_decl { | ||||||
348 | 'xml-stylesheet', | ||||||
349 | href => "chrome://global/skin/", | ||||||
350 | type => "text/css" | ||||||
351 | }; | ||||||
352 | groupbox { | ||||||
353 | caption { attr { label => 'Colors' } } | ||||||
354 | radiogroup { | ||||||
355 | for my $id ( qw< orange violet yellow > ) { | ||||||
356 | radio { | ||||||
357 | attr { | ||||||
358 | id => $id, | ||||||
359 | label => ucfirst($id), | ||||||
360 | $id eq 'violet' ? (selected => 'true') : () | ||||||
361 | } | ||||||
362 | } | ||||||
363 | } # for | ||||||
364 | } | ||||||
365 | } | ||||||
366 | }; | ||||||
367 | |||||||
368 | The first thing to do in a template class is to subclass Template::Declare | ||||||
369 | itself. This is required so that Template::Declare always knows that it's | ||||||
370 | dealing with templates. The second thing is to C | ||||||
371 | to import the set of tag subroutines you need to generate the output you want. | ||||||
372 | In this case, we've imported tags to support the creation of XUL. Other tag | ||||||
373 | sets include HTML (the default), and RDF. | ||||||
374 | |||||||
375 | Templates are created using the C keyword: | ||||||
376 | |||||||
377 | template main => sub { ... }; | ||||||
378 | |||||||
379 | The first argument is the name of the template, also known as its I |
||||||
380 | this case, the template's path is C |
||||||
381 | keep both PHP and L |
||||||
382 | anonymous subroutine that uses the tag subs (and any other necessary code) to | ||||||
383 | generate the output for the template. | ||||||
384 | |||||||
385 | The tag subs imported into your class take blocks as arguments, while a | ||||||
386 | number of helper subs take other arguments. For example, the C |
||||||
387 | helper takes as its first argument the name of the XML declaration to be | ||||||
388 | output, and then a hash of the attributes of that declaration: | ||||||
389 | |||||||
390 | xml_decl { 'xml', version => '1.0' }; | ||||||
391 | |||||||
392 | Tag subs are used by simply passing a block to them that generates the output. | ||||||
393 | Said block may of course execute other tag subs in order to represent the | ||||||
394 | hierarchy required in your output. Here, the C |
||||||
395 | C |
||||||
396 | |||||||
397 | radiogroup { | ||||||
398 | for my $id ( qw< orange violet yellow > ) { | ||||||
399 | radio { | ||||||
400 | attr { | ||||||
401 | id => $id, | ||||||
402 | label => ucfirst($id), | ||||||
403 | $id eq 'violet' ? (selected => 'true') : () | ||||||
404 | } | ||||||
405 | } | ||||||
406 | } # for | ||||||
407 | } | ||||||
408 | |||||||
409 | Note the C |
||||||
410 | element created by the tag in which they appear. In the previous example, the | ||||||
411 | C |
||||||
412 | output. | ||||||
413 | |||||||
414 | Once you've written your templates, you'll want to execute them. You do so by | ||||||
415 | telling Template::Declare what template classes to dispatch to and then asking | ||||||
416 | it to show you the output from a template: | ||||||
417 | |||||||
418 | package main; | ||||||
419 | Template::Declare->init( dispatch_to => ['MyApp::Templates'] ); | ||||||
420 | print Template::Declare->show( 'main' ); | ||||||
421 | |||||||
422 | The path passed to C |
||||||
423 | either event, the output would look like this: | ||||||
424 | |||||||
425 | |||||||
426 | |||||||
427 | |||||||
428 | |
||||||
429 | |
||||||
430 | |
||||||
431 | |
||||||
432 | |
||||||
433 | |
||||||
434 | |||||||
435 | |||||||
436 | |||||||
437 | =head2 Postprocessing | ||||||
438 | |||||||
439 | Sometimes you just want simple syntax for inline elements. The following shows | ||||||
440 | how to use a postprocessor to emphasize text _like this_. | ||||||
441 | |||||||
442 | package MyApp::Templates; | ||||||
443 | use Template::Declare::Tags; | ||||||
444 | use base 'Template::Declare'; | ||||||
445 | |||||||
446 | template before => sub { | ||||||
447 | h1 { | ||||||
448 | outs "Welcome to "; | ||||||
449 | em { "my" }; | ||||||
450 | outs " site. It's "; | ||||||
451 | em { "great" }; | ||||||
452 | outs "!"; | ||||||
453 | }; | ||||||
454 | }; | ||||||
455 | |||||||
456 | template after => sub { | ||||||
457 | h1 { "Welcome to _my_ site. It's _great_!" }; | ||||||
458 | h2 { outs_raw "This is _not_ emphasized." }; | ||||||
459 | img { src is '/foo/_bar_baz.png' }; | ||||||
460 | }; | ||||||
461 | |||||||
462 | Here we've defined two templates in our template class, with the paths | ||||||
463 | C |
||||||
464 | and C |
||||||
465 | also just specify a string to be output within a tag call, but if you need to | ||||||
466 | mix tags and plain text within a tag call, as in the C |
||||||
467 | you'll need to use C |
||||||
468 | C |
||||||
469 | |||||||
470 | Now let's have a look at how we use these templates with a post-processor: | ||||||
471 | |||||||
472 | package main; | ||||||
473 | use Template::Declare; | ||||||
474 | Template::Declare->init( | ||||||
475 | dispatch_to => ['MyApp::Templates'], | ||||||
476 | postprocessor => \&emphasize, | ||||||
477 | strict => 1, | ||||||
478 | ); | ||||||
479 | |||||||
480 | print Template::Declare->show( 'before' ); | ||||||
481 | print Template::Declare->show( 'after' ); | ||||||
482 | |||||||
483 | sub emphasize { | ||||||
484 | my $text = shift; | ||||||
485 | $text =~ s{_(.+?)_}{$1}g; | ||||||
486 | return $text; | ||||||
487 | } | ||||||
488 | |||||||
489 | As usual, we've told Template::Declare to dispatch to our template class. A | ||||||
490 | new parameter to C |
||||||
491 | should expect the template output as an argument. It can then transform that | ||||||
492 | text however it sees fit before returning it for final output. In this | ||||||
493 | example, the C |
||||||
494 | _underscores_ and turns them into C<< emphasis >> HTML elements. | ||||||
495 | |||||||
496 | We then execute both the C |
||||||
497 | ending up as: | ||||||
498 | |||||||
499 | Welcome to |
||||||
500 | my site. It's | ||||||
501 | great! | ||||||
502 | Welcome to my site. It's great! |
||||||
503 | This is _not_ emphasized. |
||||||
504 | |||||||
505 | |||||||
506 | The thing to note here is that text passed to C |
||||||
507 | through the postprocessor, and neither are attribute values (like the C's | ||||||
508 | C |
||||||
509 | |||||||
510 | =head2 Inheritance | ||||||
511 | |||||||
512 | Templates are really just methods. You can subclass your template packages to | ||||||
513 | override some of those methods: | ||||||
514 | |||||||
515 | package MyApp::Templates::GenericItem; | ||||||
516 | use Template::Declare::Tags; | ||||||
517 | use base 'Template::Declare'; | ||||||
518 | |||||||
519 | template 'list' => sub { | ||||||
520 | my ($self, @items) = @_; | ||||||
521 | div { | ||||||
522 | show('item', $_) for @items; | ||||||
523 | } | ||||||
524 | }; | ||||||
525 | template 'item' => sub { | ||||||
526 | my ($self, $item) = @_; | ||||||
527 | span { $item } | ||||||
528 | }; | ||||||
529 | |||||||
530 | package MyApp::Templates::BlogPost; | ||||||
531 | use Template::Declare::Tags; | ||||||
532 | use base 'MyApp::Templates::GenericItem'; | ||||||
533 | |||||||
534 | template 'item' => sub { | ||||||
535 | my ($self, $post) = @_; | ||||||
536 | h1 { $post->title } | ||||||
537 | div { $post->body } | ||||||
538 | }; | ||||||
539 | |||||||
540 | Here we have two template classes; the second, C |
||||||
541 | inherits from the first, C |
||||||
542 | C |
||||||
543 | templates: | ||||||
544 | |||||||
545 | package main; | ||||||
546 | use Template::Declare; | ||||||
547 | |||||||
548 | Template::Declare->init( dispatch_to => ['MyApp::Templates::GenericItem'] ); | ||||||
549 | print Template::Declare->show( 'list', 'foo', 'bar', 'baz' ); | ||||||
550 | |||||||
551 | Template::Declare->init( dispatch_to => ['MyApp::Templates::BlogPost'] ); | ||||||
552 | my $post = My::Post->new(title => 'Hello', body => 'first post'); | ||||||
553 | print Template::Declare->show( 'item', $post ); | ||||||
554 | |||||||
555 | First we execute the C
|
||||||
556 | items, and then we re-C |
||||||
557 | template with an appropriate argument. Here's the output: | ||||||
558 | |||||||
559 | |
||||||
560 | foo | ||||||
561 | bar | ||||||
562 | baz | ||||||
563 | |||||||
564 | |||||||
565 | Hello |
||||||
566 | first post |
||||||
567 | |||||||
568 | So the override of the C
|
||||||
569 | another example, see L |
||||||
570 | |||||||
571 | =head2 Wrappers | ||||||
572 | |||||||
573 | There are two levels of wrappers in Template::Declare: template wrappers and | ||||||
574 | smart tag wrappers. | ||||||
575 | |||||||
576 | =head3 Template Wrappers | ||||||
577 | |||||||
578 | C |
||||||
579 | sub, but can optionally take arguments to be passed to the wrapper sub. For | ||||||
580 | example, if you wanted to wrap all of the output of a template in the usual | ||||||
581 | HTML headers and footers, you can do something like this: | ||||||
582 | |||||||
583 | package MyApp::Templates; | ||||||
584 | use Template::Declare::Tags; | ||||||
585 | use base 'Template::Declare'; | ||||||
586 | |||||||
587 | BEGIN { | ||||||
588 | create_wrapper wrap => sub { | ||||||
589 | my $code = shift; | ||||||
590 | my %params = @_; | ||||||
591 | html { | ||||||
592 | head { title { outs "Hello, $params{user}!"} }; | ||||||
593 | body { | ||||||
594 | $code->(); | ||||||
595 | div { outs 'This is the end, my friend' }; | ||||||
596 | }; | ||||||
597 | } | ||||||
598 | }; | ||||||
599 | } | ||||||
600 | |||||||
601 | template inner => sub { | ||||||
602 | wrap { | ||||||
603 | h1 { outs "Hello, Jesse, s'up?" }; | ||||||
604 | } user => 'Jesse'; | ||||||
605 | }; | ||||||
606 | |||||||
607 | Note how the C |
||||||
608 | been declared in a C |
||||||
609 | function after the closing brace (you don't need a comma there!). | ||||||
610 | |||||||
611 | The output from the "inner" template will look something like this: | ||||||
612 | |||||||
613 | |||||||
614 | |||||||
615 | |
||||||
616 | |||||||
617 | |||||||
618 | Hello, Jesse, s'up? |
||||||
619 | This is the end, my friend |
||||||
620 | |||||||
621 | |||||||
622 | |||||||
623 | =head3 Tag Wrappers | ||||||
624 | |||||||
625 | Tag wrappers are similar to template wrappers, but mainly function as syntax | ||||||
626 | sugar for creating subroutines that behave just like tags but are allowed to | ||||||
627 | contain arbitrary Perl code and to dispatch to other tags. To create one, | ||||||
628 | simply create a named subroutine with the prototype C<(&)> so that its | ||||||
629 | interface is the same as tags. Within it, use | ||||||
630 | L |
||||||
631 | actual execution, like so: | ||||||
632 | |||||||
633 | package My::Template; | ||||||
634 | use Template::Declare::Tags; | ||||||
635 | use base 'Template::Declare'; | ||||||
636 | |||||||
637 | sub myform (&) { | ||||||
638 | my $code = shift; | ||||||
639 | |||||||
640 | smart_tag_wrapper { | ||||||
641 | my %params = @_; # set using 'with' | ||||||
642 | form { | ||||||
643 | attr { %{ $params{attr} } }; | ||||||
644 | $code->(); | ||||||
645 | input { attr { type => 'submit', value => $params{value} } }; | ||||||
646 | }; | ||||||
647 | }; | ||||||
648 | } | ||||||
649 | |||||||
650 | template edit_prefs => sub { | ||||||
651 | with( | ||||||
652 | attr => { id => 'edit_prefs', action => 'edit.html' }, | ||||||
653 | value => 'Save' | ||||||
654 | ), myform { | ||||||
655 | label { 'Time Zone' }; | ||||||
656 | input { type is 'text'; name is 'tz' }; | ||||||
657 | }; | ||||||
658 | }; | ||||||
659 | |||||||
660 | Note in the C |
||||||
661 | L |
||||||
662 | the smart wrapper. C |
||||||
663 | receive those parameters, and also handles the magic of making sure that the | ||||||
664 | tags you execute within it are properly output. Here we've used C |
||||||
665 | similarly to C | ||||||
666 | C |
||||||
667 | |||||||
668 | Executing this template: | ||||||
669 | |||||||
670 | Template::Declare->init( dispatch_to => ['My::Template'] ); | ||||||
671 | print Template::Declare->show('edit_prefs'); | ||||||
672 | |||||||
673 | Yields this output: | ||||||
674 | |||||||
675 | |||||||
676 | |||||||
677 | |||||||
678 | |||||||
679 | |||||||
680 | |||||||
681 | =head2 Class Search Dispatching | ||||||
682 | |||||||
683 | The classes passed via the C |
||||||
684 | of the templates that can be executed by subsequent calls to C |
||||||
685 | Template::Declare searches through these classes in order to find those | ||||||
686 | templates. Thus it can be useful, when you're creating your template classes | ||||||
687 | and determining which to use for particular class to C |
||||||
688 | templates that override other templates. This is similar to how an operating | ||||||
689 | system will search all the paths in the C<$PATH> environment variable for a | ||||||
690 | program to run, and to L |
||||||
691 | C |
||||||
692 | |||||||
693 | For example, say you have this template class that defines a template that | ||||||
694 | you'll use for displaying images on your Web site. | ||||||
695 | |||||||
696 | package MyApp::UI::Standard; | ||||||
697 | use Template::Declare::Tags; | ||||||
698 | use base 'Template::Declare'; | ||||||
699 | |||||||
700 | template image => sub { | ||||||
701 | my ($self, $src, $title) = @_; | ||||||
702 | img { | ||||||
703 | src is $src; | ||||||
704 | title is $title; | ||||||
705 | }; | ||||||
706 | }; | ||||||
707 | |||||||
708 | As usual, you can use it like so: | ||||||
709 | |||||||
710 | my @template_classes = 'MyApp::UI::Standard'; | ||||||
711 | Template::Declare->init( dispatch_to => \@template_classes ); | ||||||
712 | print Template::Declare->show('image', 'foo.png', 'Foo'); | ||||||
713 | |||||||
714 | We're explicitly using a reference to C<@template_classes> so that we can | ||||||
715 | manage this list ourselves. | ||||||
716 | |||||||
717 | The output of this will be: | ||||||
718 | |||||||
719 | |
||||||
720 | |||||||
721 | |||||||
722 | |||||||
723 | |||||||
724 | But say that in some sections of your site you need to have a more formal | ||||||
725 | treatment of your photos. Maybe you publish photos from a wire service and | ||||||
726 | need to provide an appropriate credit. You might write the template class like | ||||||
727 | so: | ||||||
728 | |||||||
729 | package MyApp::UI::Formal; | ||||||
730 | use Template::Declare::Tags; | ||||||
731 | use base 'Template::Declare'; | ||||||
732 | |||||||
733 | template image => sub { | ||||||
734 | my ($self, $src, $title, $credit, $caption) = @_; | ||||||
735 | div { | ||||||
736 | class is 'formal'; | ||||||
737 | img { | ||||||
738 | src is $src; | ||||||
739 | title is $title; | ||||||
740 | }; | ||||||
741 | p { | ||||||
742 | class is 'credit'; | ||||||
743 | outs "Photo by $credit"; | ||||||
744 | }; | ||||||
745 | p { | ||||||
746 | class is 'caption'; | ||||||
747 | outs $caption; | ||||||
748 | }; | ||||||
749 | }; | ||||||
750 | }; | ||||||
751 | |||||||
752 | |||||||
753 | This, too, will work as expected, but the useful bit comes in when you're | ||||||
754 | mixing and matching template classes to pass to C |
||||||
755 | rendering a page. Maybe you always pass C |
||||||
756 | C |
||||||
757 | But when the code realizes that a particular page needs the more formal | ||||||
758 | treatment, you can prepend the formal class to the list: | ||||||
759 | |||||||
760 | unshift @template_classes, 'MyApp::UI::Formal'; | ||||||
761 | print Template::Declare->show( | ||||||
762 | 'image', | ||||||
763 | 'ap.png', | ||||||
764 | 'AP Photo', | ||||||
765 | 'Clark Kent', | ||||||
766 | 'Big news' | ||||||
767 | ); | ||||||
768 | shift @template_classes; | ||||||
769 | |||||||
770 | In this way, the formal C |
||||||
771 | this output: | ||||||
772 | |||||||
773 | |
||||||
774 | |||||||
775 | Photo by Clark Kent |
||||||
776 | |||||||
777 | |||||||
778 | |||||||
779 | At the end, we've shifted the formal template class off the C |
||||||
780 | list in order to restore the template classes to the default configuration, | ||||||
781 | ready for the next request. | ||||||
782 | |||||||
783 | =head2 Template Composition | ||||||
784 | |||||||
785 | There are two methods of template composition: mixins and delegation. Their | ||||||
786 | interfaces are very similar, the only difference being the template invocant. | ||||||
787 | |||||||
788 | =head3 Mixins | ||||||
789 | |||||||
790 | Let's start with a mixin. | ||||||
791 | |||||||
792 | package MyApp::UtilTemplates; | ||||||
793 | use Template::Declare::Tags; | ||||||
794 | use base 'Template::Declare'; | ||||||
795 | |||||||
796 | template content => sub { | ||||||
797 | my $self = shift; | ||||||
798 | my @paras = @_; | ||||||
799 | h1 { $self->get_title }; | ||||||
800 | div { | ||||||
801 | id is 'content'; | ||||||
802 | p { $_ } for @paras; | ||||||
803 | }; | ||||||
804 | }; | ||||||
805 | |||||||
806 | package MyApp::Templates; | ||||||
807 | use Template::Declare::Tags; | ||||||
808 | use base 'Template::Declare'; | ||||||
809 | mix MyApp::UtilTemplates under '/util'; | ||||||
810 | |||||||
811 | sub get_title { 'Kashmir' } | ||||||
812 | |||||||
813 | template story => sub { | ||||||
814 | my $self = shift; | ||||||
815 | html { | ||||||
816 | head { | ||||||
817 | title { "My Site: " . $self->get_title }; | ||||||
818 | }; | ||||||
819 | body { | ||||||
820 | show( 'util/content' => 'first paragraph', 'second paragraph' ); | ||||||
821 | }; | ||||||
822 | }; | ||||||
823 | }; | ||||||
824 | |||||||
825 | The first template class, C |
||||||
826 | called C |
||||||
827 | C<< $self->get_title >> even though it doesn't have a C |
||||||
828 | is part of the mixin's "contract": it requires that the class it's mixed into | ||||||
829 | have a C |
||||||
830 | |||||||
831 | The second template class, C |
||||||
832 | into itself under the path C and defines a C |
||||||
833 | required by the mixin. Then, its C |
||||||
834 | as C |
||||||
835 | template under C. Get it? | ||||||
836 | |||||||
837 | Now we can use the usual template invocation: | ||||||
838 | |||||||
839 | package main; | ||||||
840 | Template::Declare->init( dispatch_to => ['MyApp::Templates'] ); | ||||||
841 | print Template::Declare->show('story'); | ||||||
842 | |||||||
843 | To appreciate our output: | ||||||
844 | |||||||
845 | |||||||
846 | |||||||
847 | |
||||||
848 | |||||||
849 | |||||||
850 | Kashmir |
||||||
851 | |
||||||
852 | fist paragraph |
||||||
853 | second paragraph |
||||||
854 | |||||||
855 | |||||||
856 | |||||||
857 | |||||||
858 | Mixins are a very useful tool for template authors to add reusable | ||||||
859 | functionality to their template classes. But it's important to pay attention to | ||||||
860 | the mixin contracts so that you're sure to implement the required API in your | ||||||
861 | template class (here, the C |
||||||
862 | |||||||
863 | =head3 Aliases | ||||||
864 | |||||||
865 | Aliases are very similar to mixins, but implement delegation as a composition | ||||||
866 | pattern, rather than mixins. The upshot is that there is no contract provided | ||||||
867 | by an aliased class: it just works. This is because the invocant is the class | ||||||
868 | from which the aliases are imported, and therefore it will dispatch to methods | ||||||
869 | defined in the aliased class. | ||||||
870 | |||||||
871 | For example, say that you wanted to output a sidebar on pages that need one | ||||||
872 | (perhaps your CMS has sidebar things). We can define a template class that | ||||||
873 | has a template for that: | ||||||
874 | |||||||
875 | package MyApp::UI::Stuff; | ||||||
876 | use Template::Declare::Tags; | ||||||
877 | use base 'Template::Declare'; | ||||||
878 | |||||||
879 | sub img_path { '/ui/css' } | ||||||
880 | |||||||
881 | template sidebar => sub { | ||||||
882 | my ($self, $thing) = @_; | ||||||
883 | div { | ||||||
884 | class is 'sidebar'; | ||||||
885 | img { src is $self->img_path . '/sidebar.png' }; | ||||||
886 | p { $_->content } for $thing->get_things; | ||||||
887 | }; | ||||||
888 | }; | ||||||
889 | |||||||
890 | Note the use of the C |
||||||
891 | used by the C |
||||||
892 | |||||||
893 | package MyApp::Render; | ||||||
894 | use Template::Declare::Tags; | ||||||
895 | use base 'Template::Declare'; | ||||||
896 | alias MyApp::UI::Stuff under '/stuff'; | ||||||
897 | |||||||
898 | template page => sub { | ||||||
899 | my ($self, $page) = @_; | ||||||
900 | h1 { $page->title }; | ||||||
901 | for my $thing ($page->get_things) { | ||||||
902 | if ($thing->is('paragraph')) { | ||||||
903 | p { $thing->content }; | ||||||
904 | } elsif ($thing->is('sidebar')) { | ||||||
905 | show( '/stuff/sidebar' => $thing ); | ||||||
906 | } | ||||||
907 | } | ||||||
908 | }; | ||||||
909 | |||||||
910 | Here our rendering template class has aliased C |
||||||
911 | C. So the C |
||||||
912 | the sidebar template. If we run this: | ||||||
913 | |||||||
914 | Template::Declare->init( dispatch_to => ['MyApp::Render'] ); | ||||||
915 | print Template::Declare->show( page => $page ); | ||||||
916 | |||||||
917 | We get output as you might expect: | ||||||
918 | |||||||
919 | My page title |
||||||
920 | Page paragraph |
||||||
921 | |||||||
922 | |||||||
923 | Sidebar paragraph |
||||||
924 | Another paragraph |
||||||
925 | |||||||
926 | |||||||
927 | Now, let's say that you have political stuff that you want to use a different | ||||||
928 | image for in the sidebar. If that's the only difference, we can subclass | ||||||
929 | C |
||||||
930 | |||||||
931 | package MyApp::UI::Stuff::Politics; | ||||||
932 | use Template::Declare::Tags; | ||||||
933 | use base 'MyApp::UI::Stuff'; | ||||||
934 | |||||||
935 | sub img_path { '/politics/ui/css' } | ||||||
936 | |||||||
937 | Now let's mix that into a politics template class: | ||||||
938 | |||||||
939 | package MyApp::Render::Politics; | ||||||
940 | use Template::Declare::Tags; | ||||||
941 | use base 'Template::Declare'; | ||||||
942 | alias MyApp::UI::Stuff::Politics under '/politics'; | ||||||
943 | |||||||
944 | template page => sub { | ||||||
945 | my ($self, $page) = @_; | ||||||
946 | h1 { $page->title }; | ||||||
947 | for my $thing ($page->get_things) { | ||||||
948 | if ($thing->is('paragraph')) { | ||||||
949 | p { $thing->content }; | ||||||
950 | } elsif ($thing->is('sidebar')) { | ||||||
951 | show( '/politics/sidebar' => $thing ); | ||||||
952 | } | ||||||
953 | } | ||||||
954 | }; | ||||||
955 | |||||||
956 | The only difference between this template class and C |
||||||
957 | it aliases C |
||||||
958 | C |
||||||
959 | |||||||
960 | Template::Declare->init( dispatch_to => ['MyApp::Render::Politics'] ); | ||||||
961 | print Template::Declare->show( page => $page ); | ||||||
962 | |||||||
963 | Yields output using the value of the subclass's C |
||||||
964 | is, the sidebar image is now F instead of | ||||||
965 | F: | ||||||
966 | |||||||
967 | My page title |
||||||
968 | Page paragraph |
||||||
969 | |||||||
970 | |||||||
971 | Sidebar paragraph |
||||||
972 | Another paragraph |
||||||
973 | |||||||
974 | |||||||
975 | =head3 Other Tricks | ||||||
976 | |||||||
977 | The delegation behavior of C |
||||||
978 | template authors to mix and match libraries of template classes as | ||||||
979 | appropriate, without worrying about side effects. You can even alias templates | ||||||
980 | in one template class into another template class if you're not the author of | ||||||
981 | that class by using the C |
||||||
982 | |||||||
983 | alias My::UI::Widgets into Your::UI::View under '/widgets'; | ||||||
984 | |||||||
985 | Now the templates defined in C |
||||||
986 | C |
||||||
987 | as well, though it's not necessarily recommended, given that you would not be | ||||||
988 | able to fulfill any contracts unless you re-opened the class into which you | ||||||
989 | mixed the templates. But in any case, authors of framework view classes might | ||||||
990 | find this functionality useful for automatically aliasing template classes | ||||||
991 | into a single dispatch template class. | ||||||
992 | |||||||
993 | Another trick is to alias or mix your templates with package variables | ||||||
994 | specific to the composition. Do so via the C |
||||||
995 | |||||||
996 | package My::Templates; | ||||||
997 | mix Some::Mixin under '/mymix', setting { name => 'Larry' }; | ||||||
998 | |||||||
999 | The templates mixed from C |
||||||
1000 | variables set for them that are accessible I |
||||||
1001 | For example, if you define this template in C |
||||||
1002 | |||||||
1003 | template howdy => sub { | ||||||
1004 | my $self = shift; | ||||||
1005 | outs "Howdy, " . $self->package_variable('name') || 'Jesse'; | ||||||
1006 | }; | ||||||
1007 | |||||||
1008 | Then C |
||||||
1009 | Larry", while the output from C |
||||||
1010 | other words, package variables defined for the mixed-in templates are | ||||||
1011 | available only to the mixins and not to the original. The same functionality | ||||||
1012 | exists for C |
||||||
1013 | |||||||
1014 | =begin comment | ||||||
1015 | |||||||
1016 | =head2 Tag Sets | ||||||
1017 | |||||||
1018 | Wherein we will eventually provide a brief tutorial on creating custom tag sets. | ||||||
1019 | |||||||
1020 | =end comment | ||||||
1021 | |||||||
1022 | =head2 Indentation configuration | ||||||
1023 | |||||||
1024 | By default, Template::Declare renders a readable XML adding end of lines and a | ||||||
1025 | one column indentation. This behavior could break a webpage design or add a | ||||||
1026 | significant amount of chars to your XML output. This could be changed by | ||||||
1027 | overwriting the default values. So, | ||||||
1028 | |||||||
1029 | $Template::Declare::Tags::TAG_INDENTATION = 0; | ||||||
1030 | $Template::Declare::Tags::EOL = ""; | ||||||
1031 | say Template::Declare->show('main'); | ||||||
1032 | |||||||
1033 | will render | ||||||
1034 | |||||||
1035 | hi |
||||||
1036 | |||||||
1037 | |||||||
1038 | =head1 METHODS | ||||||
1039 | |||||||
1040 | =head2 init | ||||||
1041 | |||||||
1042 | This I |
||||||
1043 | |||||||
1044 | =over | ||||||
1045 | |||||||
1046 | =item dispatch_to | ||||||
1047 | |||||||
1048 | An array reference of classes to search for templates. Template::Declare will | ||||||
1049 | search this list of classes in order to find a template path. | ||||||
1050 | |||||||
1051 | =item roots | ||||||
1052 | |||||||
1053 | B |
||||||
1054 | reverse order. Maintained for backward compatibility and for the pleasure of | ||||||
1055 | those who want to continue using Template::Declare the way that Jesse's | ||||||
1056 | "crack-addled brain" intended. | ||||||
1057 | |||||||
1058 | =item postprocessor | ||||||
1059 | |||||||
1060 | A coderef called to postprocess the HTML or XML output of your templates. This | ||||||
1061 | is to alleviate using Tags for simple text markup. | ||||||
1062 | |||||||
1063 | =item around_template | ||||||
1064 | |||||||
1065 | A coderef called B |
||||||
1066 | receive four arguments: a coderef to invoke to render the template, the | ||||||
1067 | template's path, an arrayref of the arguments to the template, and the coderef | ||||||
1068 | of the template itself. You can use this for instrumentation. For example: | ||||||
1069 | |||||||
1070 | Template::Declare->init(around_template => sub { | ||||||
1071 | my ($orig, $path, $args, $code) = @_; | ||||||
1072 | my $start = time; | ||||||
1073 | $orig->(); | ||||||
1074 | warn "Rendering $path took " . (time - $start) . " seconds."; | ||||||
1075 | }); | ||||||
1076 | |||||||
1077 | =item strict | ||||||
1078 | |||||||
1079 | Die in exceptional situations, such as when a template can't be found, rather | ||||||
1080 | than just warn. False by default for backward compatibility. The default may | ||||||
1081 | be changed in the future, so specifying the value explicitly is recommended. | ||||||
1082 | |||||||
1083 | =back | ||||||
1084 | |||||||
1085 | =cut | ||||||
1086 | |||||||
1087 | sub init { | ||||||
1088 | 67 | 67 | 1 | 16148 | my $class = shift; | ||
1089 | 67 | 215 | my %args = (@_); | ||||
1090 | |||||||
1091 | 67 | 100 | 231 | if ( $args{dispatch_to} ) { | |||
50 | |||||||
1092 | 66 | 275 | $class->dispatch_to( $args{dispatch_to} ); | ||||
1093 | } elsif ( $args{roots} ) { | ||||||
1094 | 1 | 4 | $class->roots( $args{roots} ); | ||||
1095 | } | ||||||
1096 | |||||||
1097 | 67 | 100 | 663 | $class->strict( $args{strict} ) if exists $args{strict}; | |||
1098 | 67 | 100 | 235 | $class->postprocessor( $args{postprocessor} ) if $args{postprocessor}; | |||
1099 | 67 | 100 | 311 | $class->around_template( $args{around_template} ) if $args{around_template}; | |||
1100 | } | ||||||
1101 | |||||||
1102 | =head2 show TEMPLATE_NAME | ||||||
1103 | |||||||
1104 | Template::Declare->show( 'howdy', name => 'Larry' ); | ||||||
1105 | my $output = Template::Declare->show('index'); | ||||||
1106 | |||||||
1107 | Call C |
||||||
1108 | template. Subsequent arguments will be passed to the template. Content | ||||||
1109 | generated by C |
||||||
1110 | output method you've chosen returns content instead of outputting it directly. | ||||||
1111 | |||||||
1112 | If called in scalar context, this method will also just return the content | ||||||
1113 | when available. | ||||||
1114 | |||||||
1115 | =cut | ||||||
1116 | |||||||
1117 | sub show { | ||||||
1118 | 101 | 101 | 1 | 54081 | my $class = shift; | ||
1119 | 101 | 163 | my $template = shift; | ||||
1120 | 101 | 251 | local %Template::Declare::Tags::ELEMENT_ID_CACHE = (); | ||||
1121 | 101 | 386 | return Template::Declare::Tags::show_page($template => @_); | ||||
1122 | } | ||||||
1123 | |||||||
1124 | =head2 Template Composition | ||||||
1125 | |||||||
1126 | Sometimes you want to mix templates from one class into another class, or | ||||||
1127 | delegate template execution to a class of templates. C |
||||||
1128 | are your keys to doing so. | ||||||
1129 | |||||||
1130 | =head3 mix | ||||||
1131 | |||||||
1132 | mix Some::Clever::Mixin under '/mixin'; | ||||||
1133 | mix Some::Other::Mixin under '/otmix', setting { name => 'Larry' }; | ||||||
1134 | mix My::Mixin into My::View, under '/mymix'; | ||||||
1135 | |||||||
1136 | Mixes templates from one template class into another class. When the mixed-in | ||||||
1137 | template is called, its invocant will be the class into which it was mixed. | ||||||
1138 | This type of composition is known as a "mixin" in object-oriented parlance. | ||||||
1139 | See L for extended examples and | ||||||
1140 | a comparison to C |
||||||
1141 | |||||||
1142 | The first parameter is the name of the template class to be mixed in. The | ||||||
1143 | C |
||||||
1144 | a C |
||||||
1145 | |||||||
1146 | The C |
||||||
1147 | mixed-in copies of templates. These are available to the templates as | ||||||
1148 | C<< $self->package_variable($varname) >>. | ||||||
1149 | |||||||
1150 | The C |
||||||
1151 | this keyword, C |
||||||
1152 | |||||||
1153 | For those who prefer a direct OO syntax for mixins, just call C |
||||||
1154 | method on the class to be mixed in. To replicate the above three examples | ||||||
1155 | without the use of the sugar: | ||||||
1156 | |||||||
1157 | Some::Clever::Mixin->mix( '/mixin' ); | ||||||
1158 | Some::Other::Mixin->mix( '/otmix', { name => 'Larry' } ); | ||||||
1159 | My::Mixin->mix( 'My::View', '/mymix' ); | ||||||
1160 | |||||||
1161 | =cut | ||||||
1162 | |||||||
1163 | sub mix { | ||||||
1164 | 11 | 11 | 1 | 16 | my $mixin = shift; | ||
1165 | 11 | 32 | my ($into, @args) = _into(@_); | ||||
1166 | 11 | 60 | $mixin->_import($into, $into, @args); | ||||
1167 | } | ||||||
1168 | |||||||
1169 | =head3 alias | ||||||
1170 | |||||||
1171 | alias Some::Clever:Templates under '/delegate'; | ||||||
1172 | alias Some::Other::Templates under '/send_to', { name => 'Larry' }; | ||||||
1173 | alias UI::Stuff into My::View, under '/mystuff'; | ||||||
1174 | |||||||
1175 | Aliases templates from one template class into another class. When an alias | ||||||
1176 | called, its invocant will be the class from which it was aliased. This type of | ||||||
1177 | composition is known as "delegation" in object-oriented parlance. See | ||||||
1178 | L for extended examples and a | ||||||
1179 | comparison to C |
||||||
1180 | |||||||
1181 | The first parameter is the name of the template class to alias. The C |
||||||
1182 | keyword tells C |
||||||
1183 | template in C |
||||||
1184 | |||||||
1185 | The C |
||||||
1186 | aliases. These are available to the templates as | ||||||
1187 | C<< $self->package_variable($varname) >>. | ||||||
1188 | |||||||
1189 | The C |
||||||
1190 | Without this keyword, C |
||||||
1191 | |||||||
1192 | For those who prefer a direct OO syntax for mixins, just call C |
||||||
1193 | method on the class to be mixed in. To replicate the above three examples | ||||||
1194 | without the use of the sugar: | ||||||
1195 | |||||||
1196 | Some::Clever:Templates->alias( '/delegate' ); | ||||||
1197 | Some::Other::Templates->alias( '/send_to', { name => 'Larry' } ); | ||||||
1198 | UI::Stuff->alias( 'My::View', '/mystuff' ); | ||||||
1199 | |||||||
1200 | =cut | ||||||
1201 | |||||||
1202 | sub alias { | ||||||
1203 | 15 | 15 | 1 | 21 | my $mixin = shift; | ||
1204 | 15 | 40 | my ($into, @args) = _into(@_); | ||||
1205 | 15 | 78 | $mixin->_import($into, undef, @args); | ||||
1206 | } | ||||||
1207 | |||||||
1208 | =head3 package_variable( VARIABLE ) | ||||||
1209 | |||||||
1210 | $td->package_variable( $varname => $value ); | ||||||
1211 | $value = $td->package_variable( $varname ); | ||||||
1212 | |||||||
1213 | Returns a value set for a mixed-in template's variable, if any were specified | ||||||
1214 | when the template was mixed-in. See L for details. | ||||||
1215 | |||||||
1216 | =cut | ||||||
1217 | |||||||
1218 | sub package_variable { | ||||||
1219 | 10 | 10 | 1 | 65 | my $self = shift; | ||
1220 | 10 | 14 | my $var = shift; | ||||
1221 | 10 | 50 | 27 | if (@_) { | |||
1222 | 0 | 0 | $TEMPLATE_VARS->{$self}->{$var} = shift; | ||||
1223 | } | ||||||
1224 | 10 | 39 | return $TEMPLATE_VARS->{$self}->{$var}; | ||||
1225 | } | ||||||
1226 | |||||||
1227 | =head3 package_variables( VARIABLE ) | ||||||
1228 | |||||||
1229 | $td->package_variables( $variables ); | ||||||
1230 | $variables = $td->package_variables; | ||||||
1231 | |||||||
1232 | Get or set a hash reference of variables for a mixed-in template. See | ||||||
1233 | L for details. | ||||||
1234 | |||||||
1235 | =cut | ||||||
1236 | |||||||
1237 | sub package_variables { | ||||||
1238 | 0 | 0 | 1 | 0 | my $self = shift; | ||
1239 | 0 | 0 | 0 | if (@_) { | |||
1240 | 0 | 0 | %{ $TEMPLATE_VARS->{$self} } = shift; | ||||
0 | 0 | ||||||
1241 | } | ||||||
1242 | 0 | 0 | return $TEMPLATE_VARS->{$self}; | ||||
1243 | } | ||||||
1244 | |||||||
1245 | =head2 Templates registration and lookup | ||||||
1246 | |||||||
1247 | =head3 resolve_template TEMPLATE_PATH INCLUDE_PRIVATE_TEMPLATES | ||||||
1248 | |||||||
1249 | my $code = Template::Declare->resolve_template($template); | ||||||
1250 | my $code = Template::Declare->has_template($template, 1); | ||||||
1251 | |||||||
1252 | Turns a template path (C |
||||||
1253 | boolean C |
||||||
1254 | in addition to public ones. C |
||||||
1255 | |||||||
1256 | First it looks through all the valid Template::Declare classes defined via | ||||||
1257 | C |
||||||
1258 | $template_name directly (or via a mixin). | ||||||
1259 | |||||||
1260 | =cut | ||||||
1261 | |||||||
1262 | sub resolve_template { | ||||||
1263 | 286 | 286 | 1 | 421 | my $self = shift; | ||
1264 | 286 | 388 | my $template_name = shift; | ||||
1265 | 286 | 100 | 948 | my $show_private = shift || 0; | |||
1266 | |||||||
1267 | 286 | 305 | my @search_packages; | ||||
1268 | |||||||
1269 | # If we're being called as a class method on T::D it means "search in any package" | ||||||
1270 | # Otherwise, it means search only in this specific package" | ||||||
1271 | 286 | 100 | 580 | if ( $self eq __PACKAGE__ ) { | |||
1272 | 246 | 258 | @search_packages = @{ Template::Declare->dispatch_to }; | ||||
246 | 688 | ||||||
1273 | } else { | ||||||
1274 | 40 | 71 | @search_packages = ($self); | ||||
1275 | } | ||||||
1276 | |||||||
1277 | 286 | 1782 | foreach my $package (@search_packages) { | ||||
1278 | 291 | 50 | 33 | 2659 | next unless ( $package and $package->isa(__PACKAGE__) ); | ||
1279 | 291 | 100 | 1012 | if ( my $coderef = $package->_has_template( $template_name, $show_private ) ) { | |||
1280 | 252 | 787 | return $coderef; | ||||
1281 | } | ||||||
1282 | } | ||||||
1283 | } | ||||||
1284 | |||||||
1285 | =head3 has_template TEMPLATE_PATH INCLUDE_PRIVATE_TEMPLATES | ||||||
1286 | |||||||
1287 | An alias for C |
||||||
1288 | |||||||
1289 | =cut | ||||||
1290 | |||||||
1291 | 53 | 53 | 1 | 4156 | sub has_template { resolve_template(@_) } | ||
1292 | |||||||
1293 | =head3 register_template( TEMPLATE_NAME, CODEREF ) | ||||||
1294 | |||||||
1295 | MyApp::Templates->register_template( howdy => sub { ... } ); | ||||||
1296 | |||||||
1297 | This method registers a template called C |
||||||
1298 | As you might guess, C |
||||||
1299 | method is mainly intended to be used internally, as you use the C | ||||||
1300 | keyword to create templates, right? | ||||||
1301 | |||||||
1302 | =cut | ||||||
1303 | |||||||
1304 | sub register_template { | ||||||
1305 | 196 | 196 | 1 | 240 | my $class = shift; | ||
1306 | 196 | 210 | my $template_name = shift; | ||||
1307 | 196 | 203 | my $code = shift; | ||||
1308 | 196 | 1778 | push @{ __PACKAGE__->templates()->{$class} }, $template_name; | ||||
196 | 872 | ||||||
1309 | 196 | 1557 | _register_template( $class, _template_name_to_sub($template_name), $code ) | ||||
1310 | } | ||||||
1311 | |||||||
1312 | =head3 register_private_template( TEMPLATE_NAME, CODEREF ) | ||||||
1313 | |||||||
1314 | MyApp::Templates->register_private_template( howdy => sub { ... } ); | ||||||
1315 | |||||||
1316 | This method registers a private template called C |
||||||
1317 | calling class. As you might guess, C |
||||||
1318 | implementation. | ||||||
1319 | |||||||
1320 | Private templates can't be called directly from user code but only from other | ||||||
1321 | templates. | ||||||
1322 | |||||||
1323 | This method is mainly intended to be used internally, as you use the | ||||||
1324 | C |
||||||
1325 | |||||||
1326 | =cut | ||||||
1327 | |||||||
1328 | sub register_private_template { | ||||||
1329 | 21 | 21 | 1 | 27 | my $class = shift; | ||
1330 | 21 | 30 | my $template_name = shift; | ||||
1331 | 21 | 17 | my $code = shift; | ||||
1332 | 21 | 24 | push @{ __PACKAGE__->private_templates()->{$class} }, $template_name; | ||||
21 | 75 | ||||||
1333 | 21 | 158 | _register_template( $class, _template_name_to_private_sub($template_name), $code ); | ||||
1334 | |||||||
1335 | } | ||||||
1336 | |||||||
1337 | =head3 buffer | ||||||
1338 | |||||||
1339 | Gets or sets the L |
||||||
1340 | |||||||
1341 | You can use it to manipulate the output from tags as they are output. It's used | ||||||
1342 | internally to make the tags nest correctly, and be output to the right place. | ||||||
1343 | We're not sure if there's ever a need for you to frob it by hand, but it does | ||||||
1344 | enable things like the following: | ||||||
1345 | |||||||
1346 | template simple => sub { | ||||||
1347 | html { | ||||||
1348 | head {} | ||||||
1349 | body { | ||||||
1350 | Template::Declare->buffer->set_filter( sub {uc shift} ); | ||||||
1351 | p { 'Whee!' } | ||||||
1352 | p { 'Hello, world wide web!' } | ||||||
1353 | Template::Declare->buffer->clear_top if rand() < 0.5; | ||||||
1354 | } | ||||||
1355 | } | ||||||
1356 | }; | ||||||
1357 | |||||||
1358 | ...which outputs, with equal regularity, either: | ||||||
1359 | |||||||
1360 | |||||||
1361 | |||||||
1362 | |||||||
1363 | WHEE! |
||||||
1364 | HELLO, WORLD WIDE WEB! |
||||||
1365 | |||||||
1366 | |||||||
1367 | |||||||
1368 | ...or: | ||||||
1369 | |||||||
1370 | |||||||
1371 | |||||||
1372 | |||||||
1373 | |||||||
1374 | |||||||
1375 | We'll leave it to you to judge whether or not that's actually useful. | ||||||
1376 | |||||||
1377 | =head2 Helpers | ||||||
1378 | |||||||
1379 | You don't need to call any of this directly. | ||||||
1380 | |||||||
1381 | =head3 into | ||||||
1382 | |||||||
1383 | $class = into $class; | ||||||
1384 | |||||||
1385 | C |
||||||
1386 | All it does is return the name of the class on which it was called. | ||||||
1387 | |||||||
1388 | =cut | ||||||
1389 | |||||||
1390 | 4 | 4 | 1 | 17 | sub into { shift } | ||
1391 | |||||||
1392 | =head2 Old, deprecated or just better to avoid | ||||||
1393 | |||||||
1394 | =head3 import_templates | ||||||
1395 | |||||||
1396 | import_templates MyApp::Templates under '/something'; | ||||||
1397 | |||||||
1398 | Like C |
||||||
1399 | That is, it mixes templates into the calling template class and does not | ||||||
1400 | support package variables for those mixins. | ||||||
1401 | |||||||
1402 | B |
||||||
1403 | new code should use C |
||||||
1404 | |||||||
1405 | =cut | ||||||
1406 | |||||||
1407 | sub import_templates { | ||||||
1408 | 11 | 11 | 1 | 21 | my $caller = scalar caller(0); | ||
1409 | 11 | 51 | shift->_import($caller, $caller, @_); | ||||
1410 | } | ||||||
1411 | |||||||
1412 | =head3 new_buffer_frame | ||||||
1413 | |||||||
1414 | $td->new_buffer_frame; | ||||||
1415 | # same as | ||||||
1416 | $td->buffer->push( private => 1 ); | ||||||
1417 | |||||||
1418 | Creates a new buffer frame, using L |
||||||
1419 | |||||||
1420 | B |
||||||
1421 | |||||||
1422 | =cut | ||||||
1423 | |||||||
1424 | sub new_buffer_frame { | ||||||
1425 | 0 | 0 | 1 | 0 | __PACKAGE__->buffer->push( private => 1 ); | ||
1426 | } | ||||||
1427 | |||||||
1428 | =head3 end_buffer_frame | ||||||
1429 | |||||||
1430 | my $buf = $td->end_buffer_frame; | ||||||
1431 | # same as | ||||||
1432 | my $buf = $td->buffer->pop; | ||||||
1433 | |||||||
1434 | Deletes and returns the topmost buffer, using L |
||||||
1435 | |||||||
1436 | B |
||||||
1437 | |||||||
1438 | =cut | ||||||
1439 | |||||||
1440 | sub end_buffer_frame { | ||||||
1441 | 0 | 0 | 1 | 0 | __PACKAGE__->buffer->pop; | ||
1442 | } | ||||||
1443 | |||||||
1444 | =head3 path_for $template | ||||||
1445 | |||||||
1446 | my $path = Template::Declare->path_for('index'); | ||||||
1447 | |||||||
1448 | Returns the path for the template name to be used for show, adjusted with | ||||||
1449 | paths used in C |
||||||
1450 | which you imported the template. This method is, therefore, deprecated. | ||||||
1451 | |||||||
1452 | =cut | ||||||
1453 | |||||||
1454 | # Deprecated in favor of dispatch_to(). | ||||||
1455 | sub roots { | ||||||
1456 | # warn "roots() has been deprecated; use dispatch_to() instead\n"; | ||||||
1457 | 1 | 1 | 1 | 3 | my $class = shift; | ||
1458 | 1 | 50 | 3 | $class->dispatch_to( [ reverse @{ +shift } ] ) if @_; | |||
1 | 5 | ||||||
1459 | 1 | 7 | return [ reverse @{ $class->dispatch_to } ]; | ||||
1 | 3 | ||||||
1460 | } | ||||||
1461 | |||||||
1462 | # Removed methods that no longer work (and were never documented anyway). | ||||||
1463 | # Remove these no-ops after a few releases (added for 0.41). | ||||||
1464 | |||||||
1465 | =begin comment | ||||||
1466 | |||||||
1467 | =head3 aliases | ||||||
1468 | |||||||
1469 | =head3 alias_metadata | ||||||
1470 | |||||||
1471 | =end comment | ||||||
1472 | |||||||
1473 | =cut | ||||||
1474 | |||||||
1475 | sub aliases { | ||||||
1476 | 0 | 0 | 1 | 0 | require Carp; | ||
1477 | 0 | 0 | Carp::cluck( 'aliases() is a deprecated no-op' ); | ||||
1478 | } | ||||||
1479 | |||||||
1480 | sub alias_metadata { | ||||||
1481 | 0 | 0 | 1 | 0 | require Carp; | ||
1482 | 0 | 0 | Carp::cluck( 'alias_metadata() is a deprecated no-op' ); | ||||
1483 | } | ||||||
1484 | |||||||
1485 | sub path_for { | ||||||
1486 | 3 | 3 | 1 | 1212 | my $class = shift; | ||
1487 | 3 | 2 | my $template = shift; | ||||
1488 | 3 | 100 | 13 | return ($class->imported_into ||'') . '/' . $template; | |||
1489 | } | ||||||
1490 | |||||||
1491 | sub _templates_for { | ||||||
1492 | 79 | 100 | 79 | 184 | my $tmpl = shift->templates->{+shift} or return; | ||
1493 | 37 | 50 | 246 | return wantarray ? @{ $tmpl } : $tmpl; | |||
37 | 82 | ||||||
1494 | } | ||||||
1495 | |||||||
1496 | sub _private_templates_for { | ||||||
1497 | 79 | 100 | 79 | 215 | my $tmpl = shift->private_templates->{+shift} or return; | ||
1498 | 10 | 50 | 70 | return wantarray ? @{ $tmpl } : $tmpl; | |||
10 | 16 | ||||||
1499 | } | ||||||
1500 | |||||||
1501 | sub _has_template { | ||||||
1502 | # Otherwise find only in specific package | ||||||
1503 | 291 | 291 | 369 | my $pkg = shift; | |||
1504 | 291 | 312 | my $template_name = shift; | ||||
1505 | 291 | 355 | my $show_private = 0 || shift; | ||||
1506 | |||||||
1507 | 291 | 100 | 100 | 571 | if ( my $coderef = $pkg->_find_template_sub( _template_name_to_sub($template_name) ) ) { | ||
100 | |||||||
1508 | 246 | 886 | return $coderef; | ||||
1509 | } elsif ( $show_private and $coderef = $pkg->_find_template_sub( _template_name_to_private_sub($template_name))) { | ||||||
1510 | 6 | 22 | return $coderef; | ||||
1511 | } | ||||||
1512 | |||||||
1513 | 39 | 208 | return undef; | ||||
1514 | } | ||||||
1515 | |||||||
1516 | sub _dispatch_template { | ||||||
1517 | 214 | 214 | 325 | my $class = shift; | |||
1518 | 214 | 261 | my $code = shift; | ||||
1519 | 214 | 367 | unshift @_, $class; | ||||
1520 | 214 | 530 | goto $code; | ||||
1521 | } | ||||||
1522 | |||||||
1523 | sub _find_template_sub { | ||||||
1524 | 355 | 355 | 423 | my $self = shift; | |||
1525 | 355 | 376 | my $subname = shift; | ||||
1526 | 355 | 2478 | return $self->can($subname); | ||||
1527 | } | ||||||
1528 | |||||||
1529 | sub _template_name_to_sub { | ||||||
1530 | 534 | 534 | 960 | return _subname( "_jifty_template_", shift ); | |||
1531 | } | ||||||
1532 | |||||||
1533 | sub _template_name_to_private_sub { | ||||||
1534 | 38 | 38 | 63 | return _subname( "_jifty_private_template_", shift ); | |||
1535 | } | ||||||
1536 | |||||||
1537 | sub _subname { | ||||||
1538 | 572 | 572 | 590 | my $prefix = shift; | |||
1539 | 572 | 50 | 1159 | my $template = shift || ''; | |||
1540 | 572 | 1475 | $template =~ s{/+}{/}g; | ||||
1541 | 572 | 745 | $template =~ s{^/}{}; | ||||
1542 | 572 | 2400 | return join( '', $prefix, $template ); | ||||
1543 | } | ||||||
1544 | |||||||
1545 | sub _register_template { | ||||||
1546 | 217 | 217 | 239 | my $self = shift; | |||
1547 | 217 | 33 | 797 | my $class = ref($self) || $self; | |||
1548 | 217 | 226 | my $subname = shift; | ||||
1549 | 217 | 208 | my $coderef = shift; | ||||
1550 | 48 | 48 | 110819 | no strict 'refs'; | |||
48 | 101 | ||||||
48 | 1682 | ||||||
1551 | 48 | 48 | 246 | no warnings 'redefine'; | |||
48 | 74 | ||||||
48 | 27122 | ||||||
1552 | 217 | 204 | *{ $class . '::' . $subname } = $coderef; | ||||
217 | 1606 | ||||||
1553 | } | ||||||
1554 | |||||||
1555 | sub _into { | ||||||
1556 | 26 | 26 | 27 | my ($into, $under); | |||
1557 | 26 | 100 | 34 | if ( eval { $_[0]->isa(__PACKAGE__) } ) { | |||
26 | 100 | 209 | |||||
1558 | 2 | 6 | ($into, $under) = (shift, shift); | ||||
1559 | 24 | 252 | } elsif ( eval { $_[1]->isa(__PACKAGE__) } ) { | ||||
1560 | 2 | 4 | ($under, $into) = (shift, shift); | ||||
1561 | } else { | ||||||
1562 | 22 | 40 | $into = caller(1); | ||||
1563 | 22 | 34 | $under = shift; | ||||
1564 | } | ||||||
1565 | 26 | 111 | return $into, $under, @_; | ||||
1566 | } | ||||||
1567 | |||||||
1568 | sub _import { | ||||||
1569 | 37 | 50 | 37 | 108 | return undef if $_[0] eq __PACKAGE__; | ||
1570 | 37 | 59 | my ($mixin, $into, $invocant, $prefix, $vars) = @_; | ||||
1571 | |||||||
1572 | |||||||
1573 | 37 | 68 | $prefix =~ s|/+/|/|g; | ||||
1574 | 37 | 96 | $prefix =~ s|/$||; | ||||
1575 | 37 | 182 | $mixin->imported_into($prefix); | ||||
1576 | |||||||
1577 | 37 | 1008 | my @packages = reverse grep { $_->isa(__PACKAGE__) } | ||||
116 | 2071 | ||||||
1578 | Class::ISA::self_and_super_path( $mixin ); | ||||||
1579 | |||||||
1580 | 37 | 82 | foreach my $from (@packages) { | ||||
1581 | 79 | 440 | for my $tname ( __PACKAGE__->_templates_for($from) ) { | ||||
1582 | 47 | 77 | my $sname = _template_name_to_sub($tname); | ||||
1583 | 47 | 66 | 319 | $into->register_template( | |||
1584 | "$prefix/$tname", | ||||||
1585 | _import_code( $sname, $from, $invocant || $mixin, $vars ) | ||||||
1586 | ); | ||||||
1587 | } | ||||||
1588 | 79 | 481 | for my $tname ( __PACKAGE__->_private_templates_for($from) ) { | ||||
1589 | 10 | 14 | my $sname = _template_name_to_private_sub($tname); | ||||
1590 | 10 | 66 | 41 | $into->register_private_template( | |||
1591 | "$prefix/$tname", | ||||||
1592 | _import_code( $sname, $from, $invocant || $mixin, $vars ) | ||||||
1593 | ); | ||||||
1594 | } | ||||||
1595 | } | ||||||
1596 | } | ||||||
1597 | |||||||
1598 | sub _import_code { | ||||||
1599 | 57 | 57 | 97 | my ($sname, $from, $mixin, $vars) = @_; | |||
1600 | 57 | 194 | my $code = $from->_find_template_sub( $sname ); | ||||
1601 | 30 | 30 | 35 | return $mixin eq $from ? $code : sub { shift; $code->($mixin, @_) } | |||
30 | 86 | ||||||
1602 | 57 | 100 | 474 | unless $vars; | |||
100 | |||||||
1603 | return sub { | ||||||
1604 | 2 | 2 | 4 | shift @_; # Get rid of the passed-in "$self" class. | |||
1605 | 2 | 8 | local $TEMPLATE_VARS->{$mixin} = $vars; | ||||
1606 | 2 | 8 | $code->($mixin, @_); | ||||
1607 | 4 | 39 | }; | ||||
1608 | } | ||||||
1609 | |||||||
1610 | =head1 PITFALLS | ||||||
1611 | |||||||
1612 | We're reusing the perl interpreter for our templating language, but Perl was | ||||||
1613 | not designed specifically for our purpose here. Here are some known pitfalls | ||||||
1614 | while you're scripting your templates with this module. | ||||||
1615 | |||||||
1616 | =over | ||||||
1617 | |||||||
1618 | =item * | ||||||
1619 | |||||||
1620 | It's quite common to see tag sub calling statements without trailing | ||||||
1621 | semi-colons right after C<}>. For instance, | ||||||
1622 | |||||||
1623 | template foo => sub { | ||||||
1624 | p { | ||||||
1625 | a { attr { src => '1.png' } } | ||||||
1626 | a { attr { src => '2.png' } } | ||||||
1627 | a { attr { src => '3.png' } } | ||||||
1628 | } | ||||||
1629 | }; | ||||||
1630 | |||||||
1631 | is equivalent to | ||||||
1632 | |||||||
1633 | template foo => sub { | ||||||
1634 | p { | ||||||
1635 | a { attr { src => '1.png' } }; | ||||||
1636 | a { attr { src => '2.png' } }; | ||||||
1637 | a { attr { src => '3.png' } }; | ||||||
1638 | }; | ||||||
1639 | }; | ||||||
1640 | |||||||
1641 | But C |
||||||
1642 | after C |
||||||
1643 | |||||||
1644 | =item * | ||||||
1645 | |||||||
1646 | Another place that requires trailing semicolon is the statements before a Perl | ||||||
1647 | looping statement, an C |
||||||
1648 | |||||||
1649 | p { "My links:" }; | ||||||
1650 | for (@links) { | ||||||
1651 | with ( src => $_ ), a {} | ||||||
1652 | } | ||||||
1653 | |||||||
1654 | The C<;> after C< p { ... } > is required here, or Perl will complain about | ||||||
1655 | syntax errors. | ||||||
1656 | |||||||
1657 | Another example is | ||||||
1658 | |||||||
1659 | h1 { 'heading' }; # this trailing semicolon is mandatory | ||||||
1660 | show 'tag_tag' | ||||||
1661 | |||||||
1662 | =item * | ||||||
1663 | |||||||
1664 | The C |
||||||
1665 | semicolon, unless it is the only statement in a block. For example, | ||||||
1666 | |||||||
1667 | p { class is 'item'; id is 'item1'; outs "This is an item" } | ||||||
1668 | img { src is 'cat.gif' } | ||||||
1669 | |||||||
1670 | =item * | ||||||
1671 | |||||||
1672 | Literal strings that have tag siblings won't be captured. So the following template | ||||||
1673 | |||||||
1674 | p { 'hello'; em { 'world' } } | ||||||
1675 | |||||||
1676 | produces | ||||||
1677 | |||||||
1678 |
|
||||||
1679 | world | ||||||
1680 | |||||||
1681 | |||||||
1682 | instead of the desired output | ||||||
1683 | |||||||
1684 |
|
||||||
1685 | hello | ||||||
1686 | world | ||||||
1687 | |||||||
1688 | |||||||
1689 | You can use C |
||||||
1690 | |||||||
1691 | p { outs 'hello'; em { 'world' } } | ||||||
1692 | |||||||
1693 | Note you can always get rid of C |
||||||
1694 | element of the containing block: | ||||||
1695 | |||||||
1696 | p { 'hello, world!' } | ||||||
1697 | |||||||
1698 | =item * | ||||||
1699 | |||||||
1700 | Look out! If the if block is the last block/statement and the condition part | ||||||
1701 | is evaluated to be 0: | ||||||
1702 | |||||||
1703 | p { if ( 0 ) { } } | ||||||
1704 | |||||||
1705 | produces | ||||||
1706 | |||||||
1707 | 0 |
||||||
1708 | |||||||
1709 | instead of the more intuitive output: | ||||||
1710 | |||||||
1711 | |||||||
1712 | |||||||
1713 | This is because C |
||||||
1714 | value of the whole block, which is used as the content of tag. |
||||||
1715 | |||||||
1716 | To get rid of this, just put an empty string at the end so it returns empty | ||||||
1717 | string as the content instead of 0: | ||||||
1718 | |||||||
1719 | p { if ( 0 ) { } '' } | ||||||
1720 | |||||||
1721 | =back | ||||||
1722 | |||||||
1723 | =head1 BUGS | ||||||
1724 | |||||||
1725 | Crawling all over, baby. Be very, very careful. This code is so cutting edge, | ||||||
1726 | it can only be fashioned from carbon nanotubes. But we're already using this | ||||||
1727 | thing in production :) Make sure you have read the L | ||||||
1728 | section above :) | ||||||
1729 | |||||||
1730 | Some specific bugs and design flaws that we'd love to see fixed. | ||||||
1731 | |||||||
1732 | =over | ||||||
1733 | |||||||
1734 | =item Output isn't streamy. | ||||||
1735 | |||||||
1736 | =back | ||||||
1737 | |||||||
1738 | If you run into bugs or misfeatures, please report them to | ||||||
1739 | C |
||||||
1740 | |||||||
1741 | =head1 SEE ALSO | ||||||
1742 | |||||||
1743 | =over | ||||||
1744 | |||||||
1745 | =item L |
||||||
1746 | |||||||
1747 | =item L |
||||||
1748 | |||||||
1749 | =item L |
||||||
1750 | |||||||
1751 | =item L |
||||||
1752 | |||||||
1753 | =item L |
||||||
1754 | |||||||
1755 | =back | ||||||
1756 | |||||||
1757 | =head1 AUTHOR | ||||||
1758 | |||||||
1759 | Jesse Vincent |
||||||
1760 | |||||||
1761 | =head1 LICENSE | ||||||
1762 | |||||||
1763 | Template::Declare is Copyright 2006-2010 Best Practical Solutions, LLC. | ||||||
1764 | |||||||
1765 | Template::Declare is distributed under the same terms as Perl itself. | ||||||
1766 | |||||||
1767 | =cut | ||||||
1768 | |||||||
1769 | 1; |