3 # Copyright (C) 2008,2009 Joshua Grams <josh@qualdan.com>
5 # This program is free software: you can redistribute it and/or modify
6 # it under the terms of the GNU General Public License as published by
7 # the Free Software Foundation, either version 3 of the License, or
8 # (at your option) any later version.
10 # This program is distributed in the hope that it will be useful,
11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 # GNU General Public License for more details.
15 # You should have received a copy of the GNU General Public License
16 # along with this program. If not, see <http://www.gnu.org/licenses/>.
19 # This is a simple template-handling system. You pass it a big data
20 # structure with key/value pairs, and a template string to fill out.
22 # Within a template, it recognizes tags of the form ~name [arg...]~,
23 # optionally wrapped in HTML comments (which will be removed along with
24 # the tag markers when the template is filled out).
26 # { and } as the final argument mark those tags as being the start and
27 # end of a sub-template (for optional or repeated sections). All other
28 # tags represent slots to be directly filled by data values. On a }
29 # tag, the name is optional, but must match the corresponding { tag if
32 # For a value tag, arguments represent encodings to be applied
33 # successively. For instance, ~foo html~ will encode it to be safe in
34 # HTML ('&' to '&', '<' to '<', and so on).
36 # { tags can take one argument, which will call the corresponding
37 # tem_auto_* function to munge the data, automating certain common use
38 # cases. See the comments on the tem_auto functions for more details.
40 require_once('code/wfpl/encode.php');
41 require_once('code/wfpl/file.php');
42 require_once('code/wfpl/misc.php');
48 function template($template, $data) {
49 return fill_template(parse_template($template), $data);
52 function template_file($filename, $data) {
53 return fill_template(parse_template_file($filename), $data);
56 function parse_template_file($filename) {
57 return parse_template(file_get_contents($filename));
60 # See also parse_template and fill_template.
63 # To track our position in the template and in the data, we use a linked
64 # stack structure. Each node is a hash with a reference to the parent
65 # node along with whatever other data you want to add. For each stack,
66 # you simply keep a variable with a reference to the top element. Then
67 # the push and pop operations are:
69 # $top =& tem_push($top);
70 # $top =& $top['parent'];
72 function &tem_push(&$stack = NULL) {
73 static $refs = array();
75 # Since a PHP reference is *not* a pointer to data, but a pointer to
76 # a variable (or array slot), we *have* to first put the new node in
77 # $refs, and then reference it from $new.
80 $new =& $refs[count($refs)-1];
81 if($stack) $new['parent'] =& $stack;
86 # First we take the template string and convert it into a tree of
87 # strings and sub-templates. A template is a hash with a name string,
88 # a pieces array, and possibly an args array.
90 function parse_template($string) {
92 $tem['pieces'] = array();
93 # note: for some reason this captures '<!--' but not '-->'.
94 $matches = preg_split("/(<!--)?(~[^~]*~)(?(1)-->)/", $string, -1, PREG_SPLIT_DELIM_CAPTURE);
95 foreach($matches as $match) {
96 if(substr($match,0,1) == '~') {
97 $args = explode(' ', substr($match,1,-1));
99 if(count($args) == 1 and $args[0] == '}') $name = '';
100 else $name = array_shift($args);
102 if(last($args) == '{') { # open block
104 # create a new sub-template
105 # and add it to the parent.
106 $tem =& tem_push($tem);
107 $tem['parent']['pieces'][] =& $tem;
108 $tem['name'] = $name;
109 $tem['pieces'] = array();
110 $tem['args'] = $args;
111 } elseif(last($args) == '}') { # close block
114 if($name && $name != $cur) {
115 die("Invalid template: tried to close '$name', but '$cur' is current.");
117 $tem =& $tem['parent'];
118 } else { # value slot
119 $tem['pieces'][] = array('name' => $name, 'args' => $args);
121 } elseif($match and $match != '<!--') { # static string
122 $tem['pieces'][] = $match;
128 # To fill out a template, we do a depth-first traversal of the template
129 # tree, replacing all tags with the data values.
131 # The data starts out as a nested set of key/value pairs, where the
134 # a string to fill a value slot
135 # a hash to fill one instance of a sub-template
136 # an array of hashes to fill multiple instances of a sub-template
138 # The middle form will be converted to the last form as we use it.
140 function tem_data_as_rows($value) {
141 if(is_array($value)) {
142 # numeric keys, is already array of arrays -- expand sub-template for each.
143 if(array_key_exists(0, $value)) return $value;
144 # key/value pairs -- expand sub-template once.
145 else return array($value);
147 # value -- expand sub-template once using only parent values
148 return array(array());
150 # empty value -- don't expand sub-template
155 # To look up a key, we check each namespace (starting with the
156 # innermost one) until a value is found.
158 function tem_find_scope($key, $context) {
161 if(array_key_exists($key, $scope['data'])) {
164 } while($scope = $scope['parent']);
166 # not found; return empty scope.
167 return array('parent' => $context);
170 function tem_get($key, $context) {
171 $scope = tem_find_scope($key, $context);
172 if($scope) return $scope['data'][$key];
175 # Return the value for a tag as a set of rows to fill a sub-template.
176 # If $tag has an arg, call the tem_auto function to munge the data.
177 function &tem_get_rows($tag, $context)
180 if(count($tag['args'])) {
181 $func = "tem_auto_" . $tag['args'][0];
182 function_exists($func)
183 or die("ERROR: template auto function '$func' not found.<br>\n");
185 $scope = tem_find_scope($key, $context);
187 if($func) $value = $func($key, $scope);
188 else $value = $scope['data'][$key];
190 $rows = tem_data_as_rows($value);
191 if(is_array($value)) $scope['data'][$key] = $rows;
196 # Return the value for a tag as an encoded string.
197 function tem_get_enc($tag, $context)
200 $value = tem_get($key, $context);
201 foreach($tag['args'] as $encoding) {
202 $func = "enc_$encoding";
203 if(function_exists($func)) $value = $func($value, $key);
204 else die("ERROR: encoder function '$func' not found.<br>\n");
209 function fill_template($template, &$data, &$context = NULL) {
211 $context =& tem_push($context);
212 $context['data'] =& $data;
215 foreach($template['pieces'] as $tem) {
216 if(is_string($tem)) $output .= $tem;
217 elseif($tem['pieces']) { # sub-template
218 $rows =& tem_get_rows($tem, $context);
219 foreach($rows as $key => &$row) {
220 $context =& tem_push($context);
221 $context['data'] =& $row;
222 $context['rows'] =& $rows;
223 $output .= fill_template($tem, $row, $context);
224 $context =& $context['parent'];
228 $output .= tem_get_enc($tem, $context);
236 # Return a hash containing the top-level sub-templates of tem.
237 function top_sub_templates($tem) {
239 foreach($tem['pieces'] as $piece) {
240 if(is_array($piece) and $piece['pieces']) {
241 $subs[$piece['name']] = $piece;
247 # Replace top-level values in $main with top-level templates from $tem.
248 function merge_templates($main, $tem) {
249 $out = array('name' => $main['name'], 'pieces' => array());
251 $subs = top_sub_templates($tem);
253 foreach($main['pieces'] as $piece) {
254 if(is_array($piece) and !$piece['pieces'] and $subs[$piece['name']]) {
255 $piece = $subs[$piece['name']];
257 $out['pieces'][] = $piece;
267 # If a { tag has an argument, the corresponding tem_auto function is called.
268 # This allows it to mangle the data to automate some common cases.
270 # 'sep' (separator) sections will be shown for all but the last parent row.
275 # <!--~separator sep {~--><hr><!--~separator }"-->
279 function tem_auto_sep($key, $context) {
280 $rows =& $context['parent']['rows'];
281 if(key($rows)) return true;
282 # else we are on the last row (cursor has hit the end and reset).
285 # 'once' sections will be shown once unless the corresponding data value
286 # is false. We check only for false; 0 or '' will not work.
288 function tem_auto_once($key, $context) {
289 if($context['data'][$key] !== false)
290 return tem_data_as_rows(true);
293 # 'evenodd' sections are given an 'evenodd' attribute whose value
294 # alternates between 'even' and 'odd'.
296 function tem_auto_evenodd($key, $context) {
297 $rows = $context['data'][$key];
299 $text = array('even', 'odd');
300 foreach($rows as $key => $value) {
301 $rows[$key]['evenodd'] = $text[$even];
304 return tem_data_as_rows($rows);