Template Tag Modifiers are attributes that are applied to constrain or transform the information returned by a template tag.

Some of the template tag modifiers that Movable Type supports by default:

• capitalize - convert all the characters output by the tag to uppercase.

• replace - perform a simple string substitution on the contents of the tag.

• word_count - instead of returning the contents directly, return an integer reflecting the number of words contained by the tag.

• ltrim and rtrim - remove white space from the left/right of the tag's contents.

And many more of course. Here are some examples using some of the tags above:

<mt:Entries id="40" capitalize="1"><mt:EntryBody></mt:Entries>

<mt:Var name="foo" replace="Byrne Reese","BR">

The following reference will walk you through the process of defining your own template tag modifiers.

Registering Your Tag Modifier

As with any plugin feature, the first step is always a visit to the config.yaml. Here is a sample config.yaml file for declaring a template tag modifier:

name: Example Plugin for Movable Type
id: Example
description: This plugin is an example plugin for Movable Type.
version: 1.0
tags:
    modifier:
    lolcats:
        handler: $Example::Example::Plugin::lolcats

Defining Your Tag Modifier's Behavior

Once the tags have been declared in your config.yaml it is time to write the code that will govern their behavior.

1. Create a plugin module called Plugin.pm in the following directory:

   /path/to/mt/plugins/Example/lib/Example/

2. Edit Plugin.pm and cut and paste the following into it using a text editor:

   package Example::Plugin;
   use strict;
   
   
   sub lolcats {
       my ($str, $val, $ctx) = @_;
       return "LOL - CAN I HAZ A $str";
   }
   
   
   1; # Every module must return true
   

When a template tag modifier is invoked, Movable Type will pass three arguments to the handler. They are:

• str - The value of the template tag's content.

• val - The value passed into the global modifier attribute. If multiple values are passed, then val will be an ARRAY.

• ctx - A reference to the template's context.