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<h1>Pipes - Transform Output with Functions</h1>

<p>Pipes allow you to pass output through functions to transform it. Use the pipe symbol <code>|</code> followed by a function name to process data.</p>

<h2>Two Ways to Use Pipes</h2>

<h3>1. Variable Pipes</h3>

<p>Apply functions to variables using <code>{echo $variable | function}</code>:</p>

{example 'fragments/pipes_1'}

<h3>2. Tag Pipes</h3>

<p>Apply functions to tag output. Pipes can be placed on the opening tag or closing tag:</p>

{example 'fragments/pipes_2'}

<h2>Pipe Timing: Opening vs Closing Tag</h2>

<p>The placement of the pipe determines <strong>when</strong> the function is applied:</p>

<ul>
  <li><strong>Opening tag</strong> <code>{tag | function}</code> - Processes data BEFORE the tag content is rendered</li>
  <li><strong>Closing tag</strong> <code>{/tag | function}</code> - Processes output AFTER the tag is finished</li>
</ul>

{example 'fragments/pipes_4'}

<h2>Chaining Pipes</h2>

<p>Chain multiple pipe functions together by separating them with <code>|</code>. Functions are applied left to right:</p>

{example 'fragments/pipes_3'}

<h2>Common Pipe Functions</h2>

<table border="1" cellpadding="10" cellspacing="0" style="border-collapse: collapse; width: 100%;">
  <tr style="background: #f0f0f0;">
    <th>Function</th>
    <th>Description</th>
    <th>Example</th>
  </tr>
  <tr>
    <td><code>upper</code></td>
    <td>Convert to uppercase</td>
    <td><code>{echo $text | upper}</code></td>
  </tr>
  <tr>
    <td><code>lower</code></td>
    <td>Convert to lowercase</td>
    <td><code>{echo $text | lower}</code></td>
  </tr>
  <tr>
    <td><code>ucwords</code></td>
    <td>Capitalize each word</td>
    <td><code>{echo $text | ucwords}</code></td>
  </tr>
  <tr>
    <td><code>trim</code></td>
    <td>Remove whitespace</td>
    <td><code>{echo $text | trim}</code></td>
  </tr>
  <tr>
    <td><code>html</code></td>
    <td>HTML encode</td>
    <td><code>{echo $text | html}</code></td>
  </tr>
  <tr>
    <td><code>replace(a,b)</code></td>
    <td>Replace text</td>
    <td><code>{echo $text | replace('old','new')}</code></td>
  </tr>
  <tr>
    <td><code>+ n</code></td>
    <td>Add number</td>
    <td><code>{echo $count | + 1}</code></td>
  </tr>
  <tr>
    <td><code>date(fmt)</code></td>
    <td>Format date</td>
    <td><code>{echo $timestamp | date('Y-m-d')}</code></td>
  </tr>
</table>

<h2>Important Rules</h2>

<ul>
  <li><strong>Use {tag 'echo'} with variables</strong> - <code>{echo $var | function}</code> NOT <code>{$var | function}</code></li>
  <li><strong>Arithmetic needs spaces</strong> - <code>{echo $x | + 1}</code> NOT <code>{echo $x | +1}</code></li>
  <li><strong>Quote string parameters</strong> - <code>{echo $x | replace('a','b')}</code></li>
  <li><strong>Functions apply left to right</strong> - <code>{echo $x | trim | upper}</code> trims first, then uppercases</li>
</ul>

<h2>When to Use Opening vs Closing Tag Pipes</h2>

<table border="1" cellpadding="10" cellspacing="0" style="border-collapse: collapse; width: 100%;">
  <tr style="background: #f0f0f0;">
    <th>Use Case</th>
    <th>Placement</th>
    <th>Example</th>
  </tr>
  <tr>
    <td>Transform input data before processing</td>
    <td>Opening tag</td>
    <td><code>{items | sort}...{/items}</code></td>
  </tr>
  <tr>
    <td>Transform final output after rendering</td>
    <td>Closing tag</td>
    <td><code>{tag}...{/tag | upper}</code></td>
  </tr>
  <tr>
    <td>Format variable values</td>
    <td>Variable pipe</td>
    <td><code>{echo $price | number_format(2)}</code></td>
  </tr>
</table>

<h2>See Also</h2>

<ul>
  <li>{tag 'echo'} - Evaluate and output expressions</li>
  <li>{tag 'functions'} - List of all pipe functions</li>
  <li>{tag 'options'} - Tag options reference</li>
</ul>

Pipes - Transform Output with Functions

Pipes allow you to pass output through functions to transform it. Use the pipe symbol | followed by a function name to process data.

Two Ways to Use Pipes

1. Variable Pipes

Apply functions to variables using {echo $variable | function}:

PHP	HTML	Result

2. Tag Pipes

Apply functions to tag output. Pipes can be placed on the opening tag or closing tag:

PHP	HTML	Result

Pipe Timing: Opening vs Closing Tag

The placement of the pipe determines when the function is applied:

Opening tag {tag | function} - Processes data BEFORE the tag content is rendered
Closing tag {/tag | function} - Processes output AFTER the tag is finished

PHP	HTML	Result

Chaining Pipes

Chain multiple pipe functions together by separating them with |. Functions are applied left to right:

PHP	HTML	Result

Common Pipe Functions

Function	Description	Example
`upper`	Convert to uppercase	`{echo $text \| upper}`
`lower`	Convert to lowercase	`{echo $text \| lower}`
`ucwords`	Capitalize each word	`{echo $text \| ucwords}`
`trim`	Remove whitespace	`{echo $text \| trim}`
`html`	HTML encode	`{echo $text \| html}`
`replace(a,b)`	Replace text	`{echo $text \| replace('old','new')}`
`+ n`	Add number	`{echo $count \| + 1}`
`date(fmt)`	Format date	`{echo $timestamp \| date('Y-m-d')}`

Important Rules

Use {echo} with variables - {echo $var | function} NOT {$var | function}
Arithmetic needs spaces - {echo $x | + 1} NOT {echo $x | +1}
Quote string parameters - {echo $x | replace('a','b')}
Functions apply left to right - {echo $x | trim | upper} trims first, then uppercases

When to Use Opening vs Closing Tag Pipes

Use Case	Placement	Example
Transform input data before processing	Opening tag	`{items \| sort}...{/items}`
Transform final output after rendering	Closing tag	`{tag}...{/tag \| upper}`
Format variable values	Variable pipe	`{echo $price \| number_format(2)}`

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