下列常量由此扩展定义，且仅在此扩展编译入 PHP 或在运行时动态载入时可用。
Swish::META_TYPE_UNDEF
(integer)
Swish::META_TYPE_STRING
(integer)
Swish::META_TYPE_ULONG
(integer)
Swish::META_TYPE_DATE
(integer)
Swish::IN_FILE_BIT
(integer)
Swish::IN_TITLE_BIT
(integer)
Swish::IN_HEAD_BIT
(integer)
Swish::IN_BODY_BIT
(integer)
Swish::IN_COMMENTS_BIT
(integer)
Swish::IN_HEADER_BIT
(integer)
Swish::IN_EMPHASIZED_BIT
(integer)
Swish::IN_META_BIT
(integer)
Swish::IN_FILE
(integer)
Swish::IN_TITLE
(integer)
Swish::IN_HEAD
(integer)
Swish::IN_BODY
(integer)
Swish::IN_COMMENTS
(integer)
Swish::IN_HEADER
(integer)
Swish::IN_EMPHASIZED
(integer)
Swish::IN_META
(integer)
Swish::IN_ALL
(integer)