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  ANSI Common Lisp   15 Arrays   15.2 Dictionary of Arrays

15.2.2 simple-array Type

simple-array, array, t

The type of an array that is not displaced to another array, has no fill pointer, and is not expressly adjustable is a subtype of type simple-array. The concept of a simple array exists to allow the implementation to use a specialized representation and to allow the user to declare that certain values will always be simple arrays.

The types simple-vector, simple-string, and simple-bit-vector are disjoint subtypes of type simple-array, for they respectively mean (simple-array t (*)), the union of all (simple-array c (*)) for any c being a subtype of type character, and (simple-array bit (*)).

Compound Type Specifier Kind:

Compound Type Specifier Syntax:
(simple-array [{element-type | *} [dimension-spec]])

dimension-spec::= rank | * | ({dimension | *}*)

Compound Type Specifier Arguments:
dimension - a valid array dimension.

element-type - a type specifier.

rank - a non-negative fixnum.

Compound Type Specifier Description:
This compound type specifier is treated exactly as the corresponding compound type specifier for type array would be treated, except that the set is further constrained to include only simple arrays.

It is implementation-dependent whether displaced arrays, vectors with fill pointers, or arrays that are actually adjustable are simple arrays.

(simple-array *) refers to all simple arrays regardless of element type, (simple-array type-specifier) refers only to those simple arrays that can result from giving type-specifier as the :element-type argument to make-array.

Allegro CL Implementation Details:

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