Context expressions

Literal

Creates a new context with the given entries. Each entry has a key and a value. The key is either a name or a string. The value can be any type.

See the naming conventions for valid key names.

{
  a: 1,
  b: 2
}
// {a:1, b:2}

{
  "a": 1,
  "b": 2
}
// {a:1, b:2}

Inside the context, the previous entries can be accessed.

{
  a: 2,
  b: a * 2
}
// {a:2, b:4}

A context value can embed other context values.

{
  a: 1,
  b: {
    c: 2
  }
}
// {a:1, b:{c:2}}

Get entry/path

a.b

Accesses the entry with the key b of the context a. The path is separated by ..

If the value of the entry b is also a context, the path can be chained (i.e. a.b.c).

{
  a: 2
}.a
// 2

{
  a: {
    b: 3
  }
}.a
// {b: 3}

{
  a: {
    b: 3
  }
}.a.b
// 3

Filter

Filters a list of context elements. It is a special kind of the filter expression for lists.

While filtering, the entries of the current context element can be accessed by their key.

[
  {
    a: "p1",
    b: 5
  },
  {
    a: "p2",
    b: 10
  }
][b > 7]
// [{a: "p2", b: 10}]

Projection

Extracts the entries of a list of context elements by a given key (i.e. a projection). It returns a list containing the values of the context elements for the given key.

[
  {
    a: "p1",
    b: 5
  },
  {
    a: "p2",
    b: 10
  }
].a
// ["p1", "p2"]