name_unique
A validator to check whether a resource’s name is unique:
<input type="text" id="name" name="name" value="" />
{% validate id="name" type={name_unique} %}
Optionally, pass an id parameter to exclude that particular id when testing
for uniqueness. This is useful when you want to exclude the name of the resource
currently being edited:
<input type="text" id="name" name="name" value="" />
{% validate id="name" type={name_unique id=id} %}
You can also pass a failure_message:
<input type="text" id="name" name="name" value="" />
{% validate id="name" type={name_unique id=id failure_message=_"Eek! Already used!"} %}