What is the "<<<" operator in laravel?

I checked PHP, it’s a bit similar to bitwise operators, but judging from the example code, it should return HTML nodes.
For example:

<code>$form = <<<FORM
        <form action="form_test" method="POST">
            <input type="hidden" name="_token" value="{$csrf_token}">
            <input type="submit" value="Test"/>
        </form>
FORM;</code>

However, FORM can be replaced by GET, and strangely, the variable $csrf_token can be used in value, but the function csrf_token() cannot be used directly
I am a little confused.

Reply content:

I checked PHP, it’s a bit similar to bitwise operators, but judging from the example code, it should return HTML nodes.
For example:

<code>$form = <<<FORM
        <form action="form_test" method="POST">
            <input type="hidden" name="_token" value="{$csrf_token}">
            <input type="submit" value="Test"/>
        </form>
FORM;</code>

However, FORM can be replaced by GET, and strangely, the variable $csrf_token can be used in value, but the function csrf_token() cannot be used directly
I am a little confused.

This is the Heredoc structure of php, it has nothing to do with the framework

http://php.net/manual/zh/lang...