+# To track our position in the template and in the data, we use a linked
+# stack structure. Each node is a hash with a reference to the parent
+# node along with whatever other data you want to add. For each stack,
+# you simply keep a variable with a reference to the top element. Then
+# the push and pop operations are:
+
+# $top =& tem_push($top);
+# $top =& $top['parent'];
+
+function &tem_push(&$stack = NULL) {
+ static $refs = array();
+
+ # Since a PHP reference is *not* a pointer to data, but a pointer to
+ # a variable (or array slot), we *have* to first put the new node in
+ # $refs, and then reference it from $new.
+
+ $refs[] = array();
+ $new =& $refs[count($refs)-1];
+ if($stack) $new['parent'] =& $stack;
+ return $new;
+}
+
+# To fill out a template, we do a depth-first traversal of the template
+# tree, replacing all tags with the data values.
+
+# The data starts out as a nested set of key/value pairs, where the
+# values can be:
+
+ # a string to fill a value slot
+ # a hash to fill one instance of a sub-template
+ # an array of hashes to fill multiple instances of a sub-template
+
+# The middle form will be converted to the last form as we use it.
+
+function tem_data_as_rows($value, $key) {
+ if(is_array($value)) {
+ # numeric keys
+ if(array_key_exists(0, $value)) {
+ if(is_array($value[0])) return $value; # already array of hashes.
+ else return columnize($value, $key);
+ # key/value pairs -- expand sub-template once.
+ } else return array($value);
+ } elseif($value || $value === 0 || $value === '0' || $value === '') {
+ # value -- expand sub-template once using only parent values
+ return array(array());
+ } else {
+ # empty value -- don't expand sub-template
+ return array();
+ }
+}
+
+# To look up a key, we check each namespace (starting with the
+# innermost one) until a value is found.
+
+function tem_data_scope($key, $context) {
+ static $refs = array();
+
+ $scope = $context;
+ do{
+ if(array_key_exists($key, $scope['data'])) {
+ return $scope;
+ }
+ } while($scope = $scope['parent']);
+
+ # not found; return empty scope.
+ $refs[] = array();
+ $ret = array();
+ $ret['parent'] =& $context;
+ $ret['data'] =& last($refs);
+ return $ret;
+}
+
+function tem_get_data($key, $context) {
+ $scope = tem_data_scope($key, $context);
+ if($scope) return $scope['data'][$key];
+}
+
+# Return the value for a tag as a set of rows to fill a sub-template.
+# If $tag has an arg, call the tem_auto function to munge the data.
+function &tem_row_data($tem, $context)
+{
+ $key = $tem['name'];
+ $scope = tem_data_scope($key, $context);
+
+ if(count($tem['args'])) {
+ $auto_func = "tem_auto_" . $tem['args'][0];
+ function_exists($auto_func)
+ or die("ERROR: template auto function '$auto_func' not found.<br>\n");
+ }
+ if($auto_func) $value = $auto_func($scope['data'][$key], $key, $scope);
+ else $value = $scope['data'][$key];
+
+ $rows = tem_data_as_rows($value, $key);
+ if(is_array($value)) $scope['data'][$key] = $rows;
+
+ return $rows;
+}
+
+# Return the value for a tag as an encoded string.
+function tem_encoded_data($tag, $context)
+{
+ $key = $tag['name'];
+ $value = tem_get_data($key, $context);
+ foreach($tag['args'] as $encoding) {
+ $func = "enc_$encoding";
+ if(function_exists($func)) $value = $func($value, $key);
+ else die("ERROR: encoder function '$func' not found.<br>\n");
+ }
+ return $value;
+}
+
+
+function is_sub_template(&$piece) {
+ return is_array($piece) and $piece['pieces'];
+}
+
+function is_value_slot(&$piece) {
+ return is_array($piece) and !$piece['pieces'];
+}
+
+# Return a hash containing the top-level sub-templates of tem.
+function top_sub_templates($tem, $is_sub = 'is_sub_template') {
+ function_exists($is_sub) or die("no such function '$is_sub'.");
+ $subs = array();
+ foreach($tem['pieces'] as $piece) {
+ if($is_sub($piece)) {
+ $subs[$piece['name']] = $piece;
+ }
+ }
+ return $subs;
+}
+
+# merge $subs (sub_templates) into variables in $main (template)
+function merge_sub_templates(&$main, &$subs) {
+ foreach($main['pieces'] as &$piece) {
+ if(is_array($piece)) { # not just text
+ if($piece['pieces']) {
+ # a sub-template in main
+ merge_sub_templates($piece, $subs);
+ } else {
+ # a value-slot in main
+ $sub = $subs[$piece['name']];
+ if($sub and $sub['args'][0] != 'hide') {
+ $piece = $subs[$piece['name']];
+ $piece['parent'] =& $main;
+ }
+ }