需要在textfield中打印变量

Im working on a WordPress-site where a reservationform is installed. I want the name of the logged on user is the defaultvalue in the "name" textfield since only loggen on users can make reservations. The php-code which builds the form looks like this (originial):

// Contact details fieldset
'contact'   => array(
'legend'    => __( 'Contact Details', 'restaurant-reservations' ),
'fields'    => array(
        'name'      => array(
        'title'         => __( 'Firmenname', 'restaurant-reservations' ),
        'request_input' => empty( $request->name ) ? '***VALUE***' : $request->name,
        'callback'      => 'rtb_print_form_text_field',
        'required'      => true,
),

This continues with other value like Mail and Phonenumber.

I need to get the value from the $user_login - variable printed in the textfield. I tried entering the variable itself, declare it, extending a string and tried to execute php-code. But nothing of this works out.

Is there any other way for printing out the variable in a textfield?

Please dont mind asking futher questions as i cant explain it that detailed.

Greets

Assuming you are using a user plugin you can just call the current users details and output the user name in the text field

 $current_user = wp_get_current_user();

// Contact details fieldset
'contact'   => array(
'legend'    => __( 'Contact Details', 'restaurant-reservations' ),
'fields'    => array(
    'name'      => array(
    'title'         => __( 'Firmenname', 'restaurant-reservations' ),
    'request_input' => $current_user->user_login,
    'callback'      => 'rtb_print_form_text_field',
    'required'      => true,
),

That should do the trick