17.3.5 make-sequence [Function]

make-sequence result-type size &key initial-element ⇒ sequence

Arguments and Values::

result-type—a sequence type specifier.

size—a non-negative integer.

initial-element—an object. The default is implementation-dependent.

sequence—a proper sequence.

Description::

Returns a sequence of the type result-type and of length size, each of the elements of which has been initialized to initial-element.

If the result-type is a subtype of list, the result will be a list.

If the result-type is a subtype of vector, then if the implementation can determine the element type specified for the result-type, the element type of the resulting array is the result of upgrading that element type; or, if the implementation can determine that the element type is unspecified (or *), the element type of the resulting array is t; otherwise, an error is signaled.

Examples::

 (make-sequence 'list 0) ⇒  ()
 (make-sequence 'string 26 :initial-element #\.) 
⇒  ".........................."
 (make-sequence '(vector double-float) 2
                :initial-element 1d0)
⇒  #(1.0d0 1.0d0)

 (make-sequence '(vector * 2) 3) should signal an error
 (make-sequence '(vector * 4) 3) should signal an error

Affected By::

The implementation.

Exceptional Situations::

The consequences are unspecified if initial-element is not an object which can be stored in the resulting sequence.

An error of type type-error must be signaled if the result-type is neither a recognizable subtype of list, nor a recognizable subtype of vector.

An error of type type-error should be signaled if result-type specifies the number of elements and size is different from that number.

See Also::

make-array , make-list

Notes::

 (make-sequence 'string 5) ≡ (make-string 5)