Construction of Lists (MIT/GNU Scheme 10.1.6)

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### 7.2 Construction of Lists

procedure: list object …

  Returns a list of its arguments.

      (list 'a (+ 3 4) 'c)                    ⇒ (a 7 c)
      (list)                                  ⇒ ()

  These expressions are equivalent:

      (list obj1 obj2 … objN)
      (cons obj1 (cons obj2 … (cons objN '()) …))

procedure: make-list k [element]

  (SRFI 1) This procedure returns a newly allocated list of length k, whose elements are all element. If element is not supplied, it defaults to the empty list.

      (make-list 4 'c)                        ⇒ (c c c c)

procedure: cons* object object …

  (SRFI 1) `cons*` is similar to `list`, except that `cons*` conses together the last two arguments rather than consing the last argument with the empty list. If the last argument is not a list the result is an improper list. If the last argument is a list, the result is a list consisting of the initial arguments and all of the items in the final argument. If there is only one argument, the result is the argument.

      (cons* 'a 'b 'c)                        ⇒ (a b . c)
      (cons* 'a 'b '(c d))                    ⇒ (a b c d)
      (cons* 'a)                              ⇒ a

  These expressions are equivalent:

      (cons* obj1 obj2 … objN-1 objN)
      (cons obj1 (cons obj2 … (cons objN-1 objN) …))

procedure: list-tabulate k init-proc
procedure: make-initialized-list k init-proc

  Returns a k-element list. Element i of the list, where 0 <= i < k, is produced by (init-proc i). No guarantee is made about the dynamic order in which init-proc is applied to these indices.

      (list-tabulate 4 values) => (0 1 2 3)

  `list-tabulate` is defined by SRFI 1.

procedure: list-copy list

  (SRFI 1) Returns a newly allocated copy of list. This copies each of the pairs comprising list. This could have been defined by

      (define (list-copy list)
        (if (null? list)
            '()
            (cons (car list)
                  (list-copy (cdr list)))))

procedure: iota count [start [step]]

  (SRFI 1) Returns a list containing the elements

      (start start+step … start+(count-1)*step)

  Count must be an exact non-negative integer, while start and step can be any numbers. The start and step parameters default to 0 and 1, respectively.

      (iota 5) ⇒ (0 1 2 3 4)
      (iota 5 0 -0.1) ⇒ (0 -0.1 -0.2 -0.3 -0.4)

procedure: vector->list vector
procedure: subvector->list vector start end

  `vector->list` returns a newly allocated list of the elements of vector.
  `subvector->list` returns a newly allocated list of the elements of the given subvector. The inverse of `vector->list` is `list->vector`.

      (vector->list '#(dah dah didah))        ⇒ (dah dah didah)

Next: Selecting List Components, Previous: Pairs, Up: Lists [Contents][Index]