Generate an abstract of a given portion of text. The syntax is
abstract(text[, maxsize[, style[, query]]])
The abstract will be less than maxsize
characters long, and
will attempt to end at a word boundary. If maxsize
is not
specified (or is less than or equal to 0) then a default size of 230
characters is used.
The style
argument is a string or integer, and allows a
choice between several different ways of creating the abstract.
Note that some of these styles require the query
argument as
well, which is a Metamorph query to look for:
dumb
(0)
Start the abstract at the top of the document.smart
(1)
This style will look for the first meaningful chunk of text,
skipping over any headers at the top of the text. This is the
default if neither style
nor query
is given.querysingle
(2)
Center the abstract contiguously on the best occurence of
query
in the document.querymultiple
(3)
Like querysingle
, but also break up the abstract into
multiple sections (separated with "...
") if needed to
help ensure all terms are visible. Also take care with URLs to
try to show the start and end.querybest
An alias for the best available query-based style; currently the
same as querymultiple
. Using querybest
in a script
ensures that if improved styles become available in future
releases, the script will automatically "upgrade" to the best
style.
If no query
is given for the query
... modes, they
fall back to dumb
mode. If a query
is given with a
non-query
... mode (dumb
/smart
), the mode is
promoted to querybest
. The current locale and index
expressions also have an effect on the abstract in the
query
... modes, so that it more closely reflects an
index-obtained hit.
SELECT abstract(STORY, 0, 1, 'power struggle')
FROM ARTICLES
WHERE ARTID = 'JT09115' ;