► |  | Version: Racket Version Checking

1 | Installed Patch Level
2 | Checking Available Versions
3 | Version Utilities

Version: Racket Version Checking
1`` Installed Patch Level
patchlevel
2`` Checking Available Versions
check-version
3`` Version Utilities
valid-version?
version->list
version<?
version<=?
alpha-version?
version->integer

7.2
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## Version: Racket Version Checking

The "version" collection contains several version-related pieces that are used by Racket. See also version from racket/base.

### 1`` Installed Patch Level

(require version/patchlevel) | package: base

> > value

> > patchlevel : exact-nonnegative-integer?

Indicates the current installed patch level, which is normally zero, but may be updated by patches to DrRacket.

### 2`` Checking Available Versions

(require version/check) | package: base

> > procedure

> > (check-version) → (or/c symbol? list?)

Checks the currently available version on the PLT website (http://download.racket-lang.org) and returns a value that indicates the current state of the current installation:

- `ok — You’re fine.

- `(ok-but ,version) — You have a fine stable version, but note that there is a newer alpha version available numbered version.

- `(newer ,version) — You have an old version. Please upgrade to version.

- `(newer ,version ,alpha) — You have an old-but-stable version, please upgrade to version; you may consider also the newer alpha version numbered alpha.

- `(error ,message) — An error occurred, and message is a string that indicates the error.

- `(error ,message ,additional-info) — An error occurred; message is a string that indicates the error, and additional-info is a string containing a system error. The additional-info content is always parenthesizes, so message is a short error and (string-append message " " additional-info) is a verbose one.

### 3`` Version Utilities

(require version/utils) | package: base

The version/utils library provides a few of convenient utilities for dealing with version strings.

> > procedure

> > (valid-version? v) → boolean?

> v : any/c

Returns #t if v is a valid Racket version string, #f otherwise.

A valid version has one of the following forms:

- ‹maj›.‹min›

- ‹maj›.‹min›.‹sub›

- ‹maj›.‹min›.‹sub›.‹rel›

subject to the following constraints:

- ‹maj›, ‹min›, ‹sub›, and ‹rel› are all canonical decimal representations of natural numbers (i.e., decimal digits with no leading 0 unless the number is exactly 0)

- ‹rel› is not 0

- ‹sub› is not 0 unless ‹rel› is included

- ‹min› has no more than two digits

- ‹sub› and ‹rel› have no more than three digits

The constraints force version numbers to be in a canonical form. For example, a would-be version string "4.3.0" must be written instead as "4.3", "4.3.1.0" must be written instead as "4.3.1", and "4" must be written as "4.0".

> > procedure

> > (version->list str)

> → (list/c integer? integer? integer? integer?)
> str : valid-version?

Returns a list of four numbers that the given version string represent.

> > procedure

> > (version<? str1 str2) → boolean?

> str1 : valid-version?
> str2 : valid-version?

Returns #t if str1 represents a version that is strictly smaller than str2, #f otherwise.

> > procedure

> > (version<=? str1 str2) → boolean?

> str1 : valid-version?
> str2 : valid-version?

Returns #t if str1 represents a version that is smaller than or equal to str2, #f otherwise.

> > procedure

> > (alpha-version? str) → boolean?

> str : valid-version?

Returns #t if the version that str represents is an alpha version.

A version number of the form ‹maj›.‹min›, ‹maj›.‹min›.‹sub›, or ‹maj›.‹min›.‹sub›.‹rel› is an alpha version if ‹min› is 90 or more, ‹sub› is 900 or more, or ‹rel› is 900 or more.

> > procedure

> > (version->integer str) → (or/c integer? #f)

> str : string?

Converts the version string into an integer. For version "X.YY.ZZZ.WWW", the result will be XYYZZZWWW. This function works also for legacy Racket versions by translating "XYY.ZZZ" to XYYZZZ000. The resulting integer can thefore be used to conveniently compare any two (valid) version strings. If the version string is invalid as either a regular version string or a legacy version string, the resulting value is #f.

Note that this is the only function that deals with legacy version strings.

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