Records and Tuples

A Record groups Values by name, like a row of a table. A Tuple groups them by position.

Records

(name: "Ada", born: 1815) // {(born: 1815, name: "Ada")}

The order of the fields does not matter, and the REPL lists them alphabetically. Read a field with .:

(name: "Ada", born: 1815).name // {"Ada"}

A Record needs a Value in every field. With an empty Bag in a field, there is no Record:

(name: "Ada", born: num:{}) // an empty Bag

Tuples

[3, 4].1 // {4}

Positions start at 0.

Maps

A Map key -> value pairs two Values:

"pen" -> 12 // {"pen" -> 12}

A Map is a Record with the fields k and v, and the REPL shows it that way: (k: "pen", v: 12).

("pen" -> 12).v // {12}

A Bag of Records is a table

Reading a field of a Bag of Records reads it from every Record:

{
  (name: "Ada", born: 1815)
  (name: "Alan", born: 1912)
}.name // {"Ada", "Alan"}

Next, describe which Values a Bag may hold.