Different behaviour than Javascript when modifying context in helper

[kohlerdominik]

The PHP Code:

require('../vendor/autoload.php');
use LightnCandy\LightnCandy;

// The Template:
$template = <<<VAREND
  Before:               {{var}}                     <br>
  (Setting Variable)    {{setvar "var" "Foo"}}      <br>
  After:                {{var}}
VAREND;

// Helpers:
$helpers = [
    'setvar' => function ($name, $value, &$options) {
        $options['data']['root'][$name] = $value;
    },
];

$phpStr = LightnCandy::compile($template, array(
    // Used compile flags
    'flags' => LightnCandy::FLAG_ERROR_EXCEPTION | LightnCandy::FLAG_HANDLEBARSJS,
    'helpers' => $helpers,
));

echo "Generated PHP Code:\n$phpStr\n";

// Input Data:
$data = array(
    'var' => 'value'
);

// Save the compiled PHP code into a php file
file_put_contents('render.php', '<?php ' . $phpStr . '?>');

// Get the render function from the php file
$renderer = include('render.php');

echo "Result:\n" . $renderer($data);
echo "\n";

Result with Lightncandy:

Before: value
(Setting Variable)
After: value

Result with handlebars.js (JSFiddle)

Before: value
(Setting Variable)
After: Foo 

The Issue:

In aboves example we see, that in handlebars.js it possible to modify the context by simply assigning a new value to the context offset. But this seems not to work the same way with Lightncandy.

Is there a different way to modify the context?

[duzun]

Here is what I found works:

// Helpers:
$helpers = [
    'setvar' => function ($name, $value, &$options) {
        $options['_this'][$name] = $value;
    },
];