my_merge_tags

my_merge_tags.php

<?php
function my_merge_tags ( $text ) {
    if ( is_user_logged_in() ) {
        global $user_ID, $user_login;

        get_currentuserinfo();

        $user = (array) get_user_meta( $user_ID );

        $userdata = array();
        $uservalues = array();

        foreach ( $user as $f => $data ) {
            $data = implode( ' ', (array) $data );

            if ( 0 < strlen( $data ) ) {
                $userdata[] = '{user:' . $f . '}';
                $uservalues[] = esc_html( $data );
            }
        }

        $user = get_userdata( $user_ID );

        $userdata[] = '{user:ID}';
        $uservalues[] = $user->ID;

        $userdata[] = '{user:user_login}';
        $uservalues[] = esc_html( $user->user_login );

        $userdata[] = '{user:display_name}';
        $uservalues[] = esc_html( $user->display_name );

        $userdata[] = '{user:user_email}';
        $uservalues[] = esc_html( $user->user_email );

        $text = str_replace( $userdata, $uservalues, $text );
    }

    $text = preg_replace( '/\{user:[\w\.]*\}/', '', $text );

    return $text;
}

<?php

$text = "hello {@pods.first_name}";
$user_id = 1;

function template_parsing($text, $user_id) {

  global $pods; // important
  $pods = pods('user', $user_id);
  $text = pods_evaluate_tags($text)
  return $text;

}

?>

pods_evaluate_tags evaluates tags like magic tags, so you'd need {@vartype.varname} instead, for mapping to pods_var( 'varname', 'vartype' )