4.3.4 Fixnums

The racket/fixnum library provides operations like fx+ that consume and produce only fixnums. The operations in this library are meant to be safe versions of unsafe operations like unsafe-fx+. These safe operations are generally no faster than using generic primitives like +.

The expected use of the racket/fixnum library is for code where the require of racket/fixnum is replaced with

(require (filtered-in

(λ (name)

(and (regexp-match #rx"^unsafe-fx" name)

(regexp-replace #rx"unsafe-" name "")))

racket/unsafe/ops))

to drop in unsafe versions of the library. Alternately, when encountering crashes with code that uses unsafe fixnum operations, use the racket/fixnum library to help debug the problems.

4.3.4.1 Fixnum Arithmetic

Changed in version 7.0.0.13 of package base: Allow zero or more arguments for fx+ and fx* and one or more arguments for fx-.

Changed in version 7.0.0.13 of package base: Allow any number of arguments for fxand, fxior, and fxxor.

Changed in version 7.0.0.13 of package base: Allow one argument, in addition to allowing two or more.

Added in version 7.3.0.11 of package base.

4.3.4.2 Fixnum Vectors

A fxvector is like a vector, but it holds only fixnums. The only advantage of a fxvector over a vector is that a shared version can be created with functions like shared-fxvector.

Two fxvectors are equal? if they have the same length, and if the values in corresponding slots of the fxvectors are equal?.

A printed fxvector starts with #fx(, optionally with a number between the #fx and (. See Reading Vectors for information on reading fxvectors and Printing Vectors for information on printing fxvectors.

The optional arguments start, stop, and step are as in in-vector.

An in-fxvector application can provide better performance for fxvector iteration when it appears directly in a for clause.