records

Records

• theory

• overview

• type system

• syntax

  • constructors
  • field projection
  • nil constant

• example

  • non-recursive example
  • recursive example

• Record Types are combining several values into a structured value similar to a struct in C. An example record definition is given by

.type Connection = [
	from : Place,
	to : Place
]

defining values of ordered pairs of places. Each record type enumerates a list of nested, named fields and their types. Records may be nested as in

.type Cargo = [
	flight : Connection,
	mass : weight
]

as well as recursive, as in

.type Path = [
	first : Connection,
	rest : Path
]

Thus, a record may contain (directly or indirectly) fields of its own type.