With blocks​

During the query rendering step, the number of occurrences of each expression are tracked. All expressions that are referenced more than once and are not explicitly defined in a WITH block (with e.with), are extracted into the nearest WITH block that encloses all usages of the expression.

const a = e.set(e.int64(1), e.int64(2), e.int64(3));
const b = e.alias(a);
e.select(e.plus(a, b)).toEdgeQL();
// WITH
//   a := {1, 2, 3},
//   b := a
// SELECT a + b

This hold for expressions of arbitrary complexity.

const newActor = e.insert(e.Person, {
  name: "Colin Farrell"
});
const newMovie = e.insert(e.Movie, {
  title: "The Batman",
  cast: newActor
});
const query = e.select(newMovie, ()=>({
  id: true,
  title: true,
  cast: { name: true }
}));

To embed WITH statements inside queries, you can short-circuit this logic with a “dependency list”. It’s an error to pass an expr to multiple e.with``s, and an error to use an expr passed to ``e.with outside of that WITH block in the query.

const newActor = e.insert(e.Person, {
  name: "Colin Farrell"
});
e.insert(e.Movie, {
  cast: e.with([newActor], // list "dependencies";
    e.select(newActor, ()=>({
      id: true,
      title: true,
    }))
  )
})