Example code showing how to put together a new custom shortcode for EE3 emails, [custom_attendee_event_list]

ee3_example.php

<?php
//* Please do NOT include the opening php tag, except of course if you're starting with a blank file

add_filter(
    'filter_hook_espresso_post_replace_shortcode_search_values',
    'my_custom_attendee_event_list_shortcode_search_value',
    10
);
add_filter(
    'filter_hook_espresso_post_replace_shortcode_replace_values',
    'my_custom_attendee_event_list_shortcode_replace_value',
    10,
    2
);
function my_custom_attendee_event_list_shortcode_search_value($SearchValues) {
    $SearchValues[] = "[custom_attendee_event_list]";
    return $SearchValues;
}
function my_custom_attendee_event_list_shortcode_replace_value($ReplaceValues, $data) {
    $custom_event_table = my_custom_event_table_markup($data);
    $ReplaceValues[] = $data->table_open 
        . $data->table_heading 
        . $custom_event_table 
        . $data->table_close;
    return $ReplaceValues;
}

// modified copy/pasta from ee3 core follows

function my_custom_event_table_markup( $data ) {

    global $wpdb;
    
    $use_venue = isset($org_options['use_venue_manager']) && $org_options['use_venue_manager'] == 'Y' ? TRUE : FALSE;
    
    $SQL = 'SELECT att.event_id, att.price_option, att.start_date, att.end_date, att.event_time, att.end_time, att.email, att.attendee_session, evt.id, evt.event_name ';   
    $SQL .= $use_venue ? ', v.name venue_name ' : ', evt.venue_title venue_name ';
    $SQL .= 'FROM ' . EVENTS_ATTENDEE_TABLE . ' att ';
    $SQL .= 'LEFT JOIN ' . EVENTS_DETAIL_TABLE . ' evt ON evt.id=att.event_id ';    
    $SQL .= $use_venue ? " LEFT JOIN " . EVENTS_VENUE_REL_TABLE . " r ON r.event_id = evt.id LEFT JOIN " . EVENTS_VENUE_TABLE . " v ON v.id = r.venue_id " : '';    
    $SQL .= 'WHERE att.email = %s AND att.attendee_session = %s';
    $SQL .= 'ORDER BY att.start_date, att.event_time';

    $events = $wpdb->get_results( $wpdb->prepare( $SQL, $data->attendee->email, $data->attendee->attendee_session ));
    
    $table_row = '';
    foreach ( $events as $event ) {
        $table_row .= "
        <tr>
            <td>" . stripslashes_deep($event->event_name) . " | " . $event->price_option . "</td>
            <td>" . event_date_display($event->start_date) . "</td>
            <td>" . event_date_display($event->event_time, get_option('time_format')) . " - " . event_date_display($event->end_time, get_option('time_format')) . "</td>
            <td>" . $event->venue_name . "<br />$data->location <br />$data->google_map_link</td>
        </tr>"; 
    }
    $custom_questions = '';
    //Output custom questions
    if (function_exists('event_espresso_custom_questions_output')) {
        //Create the question display
        $email_questions_r = event_espresso_custom_questions_output(
            array(
                'attendee_id' => $data->attendee->id, 
                'all_questions' => TRUE
            )
        );
        if ($email_questions_r != '') {
            $custom_questions = '<tr><td colspan = "6">' 
            . $email_questions_r 
            . '</td></tr>';
        }
    }
    return $table_row . $custom_questions;
}