function for calculating an age based on a date

{{function name='age'}}{{strip}}
    {{$parts = '-'|explode:$date}}
    {{$yearDiff  = "Y"|date - $parts[0]}}
    {{$monthDiff = "m"|date - $parts[1]}}
    {{$dayDiff   = "d"|date - $parts[2]}}
    {{if $monthDiff lt 0}}
       {{$yearDiff = $yearDiff - 1}}
    {{else}}
       {{if $monthDiff eq 0 && $dayDiff lt 0}}
           {{$yearDiff = $yearDiff - 1}}
       {{/if}}
    {{/if}}
    {{$yearDiff}}
{{/strip}}{{/function}}

{{customer field='birthday' assign='birthday' default='1998-01-01'}}
{{age date=$birthday}} years

Output:

25 years

function with data enrichment

{{function name='list' level=0}}{{strip}}
      <ul class="level{{$level}}">
     {{foreach $data as $entry}}
         {{if count($entry) > 1}}
         <li>{{$entry@key}}</li>
             {{list data=$entry level=$level+1}}
        {{else}}
        <li>{{$entry}}</li>
        {{/if}}
     {{/foreach}}
     </ul>
{{/strip}}{{/function}}

{{* create an array to demonstrate *}}
{{$menu = ['item1','item2','item3' => ['item3-1','item3-2','item3-3'],'item4']}}

{{* run the array through the function *}}
{{list data=$menu}}

Output:

<ul class="level0">
   <li>item1</li>
   <li>item2</li>
   <li>item3</li>
   <ul class="level1">
      <li>item3-1</li>
      <li>item3-2</li>
      <li>item3-3</li>
   </ul>
</ul>

function to determine the current quarter

{{function name='currentQuarter'}}
        {{$currentMonth = $smarty.now|date_format:'%m'}}
        {{if $currentMonth lte 3}}
           {{$return = 1}}
        {{else if $currentMonth lte 6}}
           {{$return = 2}}
        {{else if $currentMonth lte 9}}
           {{$return = 3}}
        {{else}}
           {{$return = 4}}
        {{/if}}
        {{$return}}
{{/function}}

The current quarter is: {{currentQuarter}}

Output based on the month July:

The current quarter is: 3