racket/pkgs/racket-doc/version/version.scrbl
2018-10-11 09:17:15 -06:00

151 lines
5.4 KiB
Racket

#lang scribble/doc
@(require scribble/manual
scribble/bnf
(for-label version/patchlevel
version/check
version/utils
racket/base
racket/contract))
@(define (selflink s) (link s (tt s)))
@title{Version: Racket Version Checking}
The @filepath{version} collection contains several version-related
pieces that are used by Racket. See also @racket[version] from
@racketmodname[racket/base].
@; ----------------------------------------------------------------------
@section{Installed Patch Level}
@defmodule[version/patchlevel]
@defthing[patchlevel exact-nonnegative-integer?]{
Indicates the current installed patch level, which is normally zero,
but may be updated by patches to DrRacket.}
@; ----------------------------------------
@section{Checking Available Versions}
@defmodule[version/check]
@defproc[(check-version) (or/c symbol? list?)]{
Checks the currently available version on the PLT website
(@selflink["http://download.racket-lang.org"]) and returns a value that
indicates the current state of the current installation:
@itemize[
@item{@racket[`ok] --- You're fine.}
@item{@racket[`(ok-but ,_version)] --- You have a fine stable
version, but note that there is a newer alpha version available
numbered @racket[_version].}
@item{@racket[`(newer ,_version)] --- You have an old
version. Please upgrade to @racket[_version].}
@item{@racket[`(newer ,_version ,_alpha)] --- You have an
old-but-stable version, please upgrade to @racket[_version]; you
may consider also the newer alpha version numbered
@racket[_alpha].}
@item{@racket[`(error ,_message)] --- An error occurred, and
@racket[_message] is a string that indicates the error.}
@item{@racket[`(error ,_message ,_additional-info)] --- An error
occurred; @racket[_message] is a string that indicates the
error, and @racket[_additional-info] is a string containing a
system error. The @racket[_additional-info] content is always
parenthesizes, so @racket[message] is a short error and
@racket[(string-append message " " additional-info)] is a
verbose one.}
]}
@; ----------------------------------------------------------------------
@section{Version Utilities}
@defmodule[version/utils]{
The @racketmodname[version/utils] library provides a few of convenient
utilities for dealing with version strings.}
@defproc[(valid-version? [v any/c]) boolean?]{
Returns @racket[#t] if @racket[v] is a valid Racket version
string, @racket[#f] otherwise.
A valid version has one of the following forms:
@itemlist[
@item{@nonterm{maj}@litchar{.}@nonterm{min}}
@item{@nonterm{maj}@litchar{.}@nonterm{min}@litchar{.}@nonterm{sub}}
@item{@nonterm{maj}@litchar{.}@nonterm{min}@litchar{.}@nonterm{sub}@litchar{.}@nonterm{rel}}
]
subject to the following constraints:
@itemlist[
@item{@nonterm{maj}, @nonterm{min}, @nonterm{sub}, and
@nonterm{rel} are all canonical decimal representations of
natural numbers (i.e., decimal digits with no leading
@litchar{0} unless the number is exactly @litchar{0})}
@item{@nonterm{rel} is not @litchar{0}}
@item{@nonterm{sub} is not @litchar{0} unless @nonterm{rel} is included}
@item{@nonterm{min} has no more than two digits}
@item{@nonterm{sub} and @nonterm{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 @racket["4.3.0"] must be written
instead as @racket["4.3"], @racket["4.3.1.0"] must be written
instead as @racket["4.3.1"], and @racket["4"] must be written as
@racket["4.0"].}
@defproc[(version->list [str valid-version?])
(list/c integer? integer? integer? integer?)]{
Returns a list of four numbers that the given version string
represent.}
@defproc[(version<? [str1 valid-version?] [str2 valid-version?]) boolean?]{
Returns @racket[#t] if @racket[str1] represents a version that is
strictly smaller than @racket[str2], @racket[#f] otherwise.}
@defproc[(version<=? [str1 valid-version?] [str2 valid-version?]) boolean?]{
Returns @racket[#t] if @racket[str1] represents a version that is
smaller than or equal to @racket[str2], @racket[#f] otherwise.}
@defproc[(alpha-version? [str valid-version?]) boolean?]{
Returns @racket[#t] if the version that @racket[str] represents is an
alpha version.
A version number of the form @nonterm{maj}@litchar{.}@nonterm{min},
@nonterm{maj}@litchar{.}@nonterm{min}@litchar{.}@nonterm{sub},
or @nonterm{maj}@litchar{.}@nonterm{min}@litchar{.}@nonterm{sub}@litchar{.}@nonterm{rel}
is an alpha version if @nonterm{min} is @litchar{90} or more,
@nonterm{sub} is @litchar{900} or more, or @nonterm{rel} is
@litchar{900} or more.}
@defproc[(version->integer [str string?]) (or/c integer? #f)]{
Converts the version string into an integer. For version
@racket["X.YY.ZZZ.WWW"], the result will be @racketvalfont{XYYZZZWWW}.
This function works also for legacy Racket versions by
translating @racket["XYY.ZZZ"] to @racketvalfont{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 @racket[#f].
Note that this is the only function that deals with legacy version
strings.}