Page Comparison

Persistents in condition statements are accessed in the same way as in the prelude.

The following action will fire when the persistent variable ent:archive_pages is greater than 3:

if ent:archive_pages > 3 then 
notify(...)

Persistent flags and counters can also be tested with an associated timeframe. For example, the following action will fire when persistent variable ent:archive_pages is greater than 3 and the last time it as set was within the last two hours:

if ent:archive_pages > 3 within 2 hours then notify(...)

The syntax of timeframe-limited predicates is as follows:

<pvar> (<= | >= | < | > | == | !=) <expr> 
   within <expr> (weeks| days| hours | minutes| seconds)

where <pvar> is a persistent flag or counter and <expr> is any valid KRL expression that returns a number.

Persistent trails can be tested using the seen predicate. There are two forms. The first form asks whether a regular expression has been seen within an optional timeframe (specified exactly as above). So, you can say:

if seen re#/archive/2006# in ent:my_trail then
  notify(...) 

or

if seen re#/archive/2006# in ent:my_trail within 3 days then
  notify(...) 

The second form of special predicates for trails allows for checking whether a match of one regular expression appears before an item matched by another. This example would fire the action when a place matching the regular expression re#/archive/2006# was put on the trail before a place matching the regular expression re#/archive/2007#.

if seen re#/archive/2006# before re#/archive/2007# in ent:my_trail then 
  notify(...) 

...

 event:send(...)