Tag Callbacks

This example shows using tag callbacks to call php functions or methods.
In this example we use the default text "Some text for example"

• Standard tags look like {tagname} or {tagarray.indexname} for arrays
• Tags with comments look like {tagname# Comment} or {tagname # Comment}
• Tags with callbacks look like {tagname|function} (using vertical bar or pipe symbol)
• They can all be combined {tagarray.indexname|function#Comment}

• Simple callback {example1|strtoupper}: SOME TEXT FOR EXAMPLE 1
• Simple callback (same tag different callback) {example1|strtolower}: some text for example 1
• Chained callbacks {example2|strtolower|ucwords}: Some Text For Example 2
• Multi-parameter callback {example3|str_replace('Some', 'Replaced', %s)}: Replaced text for example 3
• Subclassed method callback {example4|my_custom_callback}: Some text for example 4
• Taking things to the limit {example5|strtolower|ucwords|str_replace('Some', 'Replaced', %s)|my_custom_callback}: Replaced Text For Example 5

Any methods you create in a sub-class of XTemplate (e.g. my_class extends XTemplate) are automatically available as a callback and will take priority over function calls of the same name.
Additionally, the following callback functions are available as standard (can be altered in XTemplate::allowed_callbacks array):

strtoupper, strtolower, ucwords, ucfirst, strrev, str_word_count, strlen, str_replace, str_ireplace, preg_replace, strip_tags, stripcslashes, stripslashes, str_pad, str_repeat, strtr, trim, ltrim, rtrim, nl2br, wordwrap, printf, sprintf, htmlentities, html_entity_decode, htmlspecialchars, htmlspecialchars_decode, urlencode, urldecode, date, idate, strtotime, strftime, getdate, gettimeofday, number_format, money_format, var_dump, print_r,