24.1 Introduction

Library organisation

The functions are split in a high level library, (vicare containers vectors), and a low level one, (vicare containers vectors low). The main difference between the two layers is that the high level library makes heavy usage of macros to implement the vector views, which allow accessing subvectors using a friendly syntax.

All the functions in the low level library are bound to identifiers starting with %; for example: vector-prefix? is a high level macro, %vector-prefix? is its low level function homologous.

Direction of iteration

The library accesses the values of a vector in left–to–right or right–to–left order depending on the convenience of the algorithm.

Handling side effects

Care must be taken when using functions with side effects. One reason for this is that some of the supported Scheme implementations will treat a literal vector as a constant, so the following raises an error:

(import (rnrs))

(define vec '#(0 1 2 3 4))
(vector-set! vec 2 #\9)

To avoid this problem completely, we can change the program in this way:

(import (rnrs))

(define vec (vector-copy '#(0 1 2 3 4)))
(vector-set! vec 2 #\9)

of course we may want to wrap into vector-copy only the vectors that are meant to be mutated.