Especially when debugging queries it can often be interesting to know whether a predicate (or a relation) holds or not. However, you can only use expressions in result sets, requiring you to manually get a boolean value for the predicate in question, e.g.:

import java

from Method m, boolean isStatic
where
  if m.isStatic() then isStatic = true
  else isStatic = false
select m, isStatic

Therefore it might be useful to introduce a boolean(<formula>) expression. If the formula holds, then the result is true, otherwise false:

import java

from Method m
select m, boolean(m.isStatic())