Time expressions

For time expressions it has proven useful to go the path of instant completion [Birkenhauer1998]. Wherever a time expression is encountered the system tries to find a sponsoring expression (either in the focus or in the situative context, i.e. the time of the dialogue) and completes the new expression (see examples).

A01:

Why not meet on the fourth of June?
{month:june, day_of_month:4}

B02:

The sixth would be better, I'm afraid.
{, day_of_month:6}

A03:

So is it going to be the eigth or the ninth?
or({day_of_month:8}, {day_of_month:9})

B04:

A Friday? Yes, Friday's good.
{, day_of_week:friday}

A05:

Six o'clock looks like a good time for me.
{time_of_day:6:0})

B06:

Couldn't we do it before?
before()

Our approach makes use of the temporal specification tree in fig. 4. A complete temporal expression is defined as contiguous path from the most specific node (that would be counted day of month in the first example) to the root node (YEAR). The completion of a time expression uses this tree to find out the missing temporal data that has to be taken from the sponsoring expression.