CLHS: Function MAKE-SEQUENCE

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Function MAKE-SEQUENCE

Syntax:

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)

The following X3J13 cleanup issues, not part of the specification, apply to this section:

- CHARACTER-PROPOSAL:2-6-5
- SEQUENCE-TYPE-LENGTH:MUST-MATCH
- ARGUMENTS-UNDERSPECIFIED:SPECIFY
- CONCATENATE-SEQUENCE:SIGNAL-ERROR

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