Class Cons

Symbolic expressions are built by connecting Cons structures.

For example, (a * b + c) is built like this:

The car links go downwards, the cdr links go to the right.

      _______      _______                                            _______      _______
     |cons   |--->|cons   |----------------------------------------->|cons   |--->|nil    |
     |       |    |       |                                          |       |    |       |
     |_______|    |_______|                                          |_______|    |_______|
         |            |                                                  |
      ___v___      ___v___      _______      _______      _______     ___v___
     |   +   |    |cons   |--->|cons   |--->|cons   |--->|nil    |   |   c   |
     |       |    |       |    |       |    |       |    |       |   |       |
     |_______|    |_______|    |_______|    |_______|    |_______|   |_______|
                      |            |            |
                   ___v___      ___v___      ___v___
                  |   *   |    |   a   |    |   b   |
                  |       |    |       |    |       |
                  |_______|    |_______|    |_______|

A nil is a special kind of Cons in which the iscons method returns false. An atom is never in the cdr position. There will be a cons with a nil cdr and a car containing the atom.

Hierarchy (view full)

Implements

Constructors

constructor

Properties

end? pos?

Accessors

arg argList base car cdr expo head iscons isnil item0 item1 item2 item3 item4 length lhs name opr rest rhs

Methods

[iterator] addRef contains equals item map release tail toString

Constructors

constructor

  • new Cons(car, cdr, pos?, end?): Cons

  • Parameters

    • car: U
    • cdr: Cons
    • Optional pos: number
    • Optional end: number

    Returns Cons

Properties

Optional Readonly end

end?: number

Optional Readonly pos

pos?: number

Accessors

arg

  • get arg(): U

  • A convenience property for the method item(1). A useful shortcut when working with unary operators. The returned item is reference counted.

    Returns U

argList

  • get argList(): Cons

  • Exactly the same as the cdr property. Used for code-as-documentation. The returned item is reference counted.

    Returns Cons

base

  • get base(): U

  • An convenience for cdr.car for use with (power base expo) expressions.

    Returns U

car

  • get car(): U

  • Returns the car property if it is defined, otherwise nil. The returned item is reference counted.

    Returns U

cdr

  • get cdr(): Cons

  • Returns the cdr property if it is defined, otherwise nil. The returned item is reference counted.

    Returns Cons

expo

  • get expo(): U

  • An convenience for cdr.cdr.car for use with (power base expo) expressions.

    Returns U

head

  • get head(): U

  • Exactly the same as the car property. Used for code-as-documentation. The returned item is reference counted.

    Returns U

iscons

  • get iscons(): boolean

  • Returns boolean

isnil

  • get isnil(): boolean

  • Returns boolean

item0

item1

item2

item3

item4

length

  • get length(): number

  • Returns the length of the list.

    Returns number

lhs

  • get lhs(): U

  • A convenience property for the method item(1). A useful shortcut when working with binary operators. The returned item is reference counted.

    Returns U

name

  • get name(): "Cons" | "Nil"

  • Contains the name of the type.

    Returns "Cons" | "Nil"

opr

  • get opr(): U

  • A convenience property for the method item(0). A useful shortcut when working with operators. The returned item is reference counted.

    Returns U

rest

  • get rest(): Cons

  • Exactly the same as the cdr property. Used for code-as-documentation. The returned item is reference counted.

    Returns Cons

rhs

  • get rhs(): U

  • A convenience property for the method item(2). A useful shortcut when working with binary operators. The returned item is reference counted.

    Returns U

Methods

[iterator]

  • [iterator](): Generator<U, void, unknown>

  • Provides an iterator over the Cons, returning the items is the list. The first element returned will be car(cons). The subsequent elements are obtained from walking the cdr's. Hint: Using the ... operator inside [] returns all the items in the list.

    Returns Generator<U, void, unknown>

addRef

contains

  • contains(needle): boolean

  • Parameters

    • needle: U

    Returns boolean

equals

  • equals(other): boolean

  • Parameters

    • other: U

    Returns boolean

item

  • item(index): U

  • Returns the item at the specified (zero-based) index. The returned item is reference counted.

    (item0 item1 item2 ...)

    Parameters

    • index: number

    Returns U

map

  • map(f): Cons

  • Maps the elements of the list using a mapping function.

    Parameters

    • f: ((a) => U)
        • (a): U

        • Parameters

          Returns U

    Returns Cons

release

tail

  • tail(): U[]

  • Return everything except the first item in the list as a JavaScript array.

    Returns U[]

toString

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