for-loop-examples.md

For Loop Examples for Templex

The for loop feature allows you to create iterative logic with initialization, condition, and increment expressions, similar to for loops in programming languages.

Basic Syntax

<{ for( $variable = start; condition; increment ) }>
    Content to repeat
<{ endfor }>

Examples

Basic Counting Loop

<{ for( $i = 0; $i < 5; $i++ ) }>
    <p>Iteration <{ $i }></p>
<{ endfor }>

Countdown Loop

<{ for( $i = 10; $i > 0; $i-- ) }>
    <p>Countdown: <{ $i }></p>
<{ endfor }>

Step Increment

<{ for( $i = 0; $i < 20; $i += 5 ) }>
    <p>Value: <{ $i }></p>
<{ endfor }>

Step Decrement

<{ for( $i = 100; $i > 0; $i -= 10 ) }>
    <p>Countdown by 10: <{ $i }></p>
<{ endfor }>

Using Variables for Limits

<{ for( $i = $startValue; $i <= $endValue; $i++ ) }>
    <p>Number: <{ $i }></p>
<{ endfor }>

Different Comparison Operators

<!-- Less than or equal -->
<{ for( $i = 1; $i <= 3; $i++ ) }>
    <p>Item <{ $i }></p>
<{ endfor }>

<!-- Greater than or equal -->
<{ for( $i = 5; $i >= 1; $i-- ) }>
    <p>Reverse: <{ $i }></p>
<{ endfor }>

Nested For Loops

<{ for( $row = 1; $row <= 3; $row++ ) }>
    <div class="row">
        <{ for( $col = 1; $col <= 3; $col++ ) }>
            <span class="cell">(<{ $row }>,<{ $col }>)</span>
        <{ endfor }>
    </div>
<{ endfor }>

Creating Tables

<table>
    <{ for( $row = 1; $row <= $rows; $row++ ) }>
        <tr>
            <{ for( $col = 1; $col <= $cols; $col++ ) }>
                <td>Cell <{ $row }>-<{ $col }></td>
            <{ endfor }>
        </tr>
    <{ endfor }>
</table>

Generating Lists

<ul>
    <{ for( $i = 1; $i <= $itemCount; $i++ ) }>
        <li>List item number <{ $i }></li>
    <{ endfor }>
</ul>

Supported Features

Initialization Patterns

• Simple assignment: $i = 0
• Variable assignment: $i = $startValue
• Any variable name: $counter = 1, $index = 0

Condition Operators

• Less than: $i < 10
• Less than or equal: $i <= 10
• Greater than: $i > 0
• Greater than or equal: $i >= 0
• Equal: $i == 5
• Strict equal: $i === 5
• Not equal: $i != 5
• Strict not equal: $i !== 5

Increment Types

• Post-increment: $i++ (adds 1)
• Post-decrement: $i-- (subtracts 1)
• Addition assignment: $i += 2 (adds specified value)
• Subtraction assignment: $i -= 2 (subtracts specified value)

Data Types

• Integers: $i = 0, $i < 10
• Variables: $i = $start, $i <= $end
• Expressions: Any valid numeric expression

Loop Metadata

For loops expose metadata variables inside the loop body:

Variable	Description
$loop_index	Zero-based iteration index (0, 1, 2, ...)
$loop_count	Total number of iterations
$loop_first	true on the first iteration
$loop_last	true on the last iteration

Note that $loop_index is the iteration count (starting from 0), while the loop variable (e.g. $i) holds the actual value which may differ when using step increments.

Highlighting First and Last Rows

<{ for( $i = 1; $i <= $totalRows; $i++ ) }>
    <tr<{ if( $loop_first ) }> class="first"<{ endif }><{ if( $loop_last ) }> class="last"<{ endif }>>
        <td>Row <{ $i }></td>
    </tr>
<{ endfor }>

Showing Progress

<{ for( $i = 0; $i < $steps; $i++ ) }>
    Processing step <{ $loop_index }> of <{ $loop_count }>...
<{ endfor }>

Advanced Examples

Creating Pagination

<div class="pagination">
    <{ for( $page = 1; $page <= $totalPages; $page++ ) }>
        <{ if( $page === $currentPage ) }>
            <span class="current"><{ $page }></span>
        <{ else }>
            <a href="?page=<{ $page }>"><{ $page }></a>
        <{ endif }>
    <{ endfor }>
</div>

Building Navigation Menus

<nav>
    <{ for( $level = 1; $level <= $maxLevel; $level++ ) }>
        <ul class="level-<{ $level }>">
            <{ for( $item = 1; $item <= $itemsPerLevel; $item++ ) }>
                <li><a href="/level<{ $level }>/item<{ $item }>">Item <{ $item }></a></li>
            <{ endfor }>
        </ul>
    <{ endfor }>
</nav>

Usage with PHP

use Myerscode\Templex\Templex;

$templex = new Templex(__DIR__ . '/templates/');

$data = [
    'startValue' => 1,
    'endValue' => 5,
    'rows' => 3,
    'cols' => 4,
    'itemCount' => 10
];

$result = $templex->render('my-template.stub', $data);
echo $result;

Performance Notes

• For loops are processed at template compilation time
• Large loops (1000+ iterations) may impact performance
• Consider using foreach loops for array iteration instead
• Nested loops multiply iteration counts (3x3 = 9 iterations)

Best Practices

1. Use meaningful variable names: $row, $item, $index instead of $i
2. Avoid infinite loops: Always ensure the condition will eventually be false
3. Consider alternatives: Use foreach for arrays, if for simple conditions
4. Limit nesting: Deep nesting can make templates hard to read
5. Use variables for limits: Makes templates more flexible and reusable