@@ -532,9 +532,11 @@ It is a good idea to strip commit identifiers in the @code{version}
field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
aesthetics have a role to play here) as well as problems related to OS
limits such as the maximum shebang length (127 bytes for the Linux
-kernel). It is best to use the full commit identifiers in
-@code{origin}s, though, to avoid ambiguities. A typical package
-definition may look like this:
+kernel). There are helper functions for doing this for packages using
+@code{git-fetch} or @code{hg-fetch} (see below). It is best to use the
+full commit identifiers in @code{origin}s, though, to avoid ambiguities.
+A typical package definition may look like this:
+
@lisp
(define my-package
@@ -553,6 +555,20 @@ definition may look like this:
)))
@end lisp
+@deffn {Scheme Procedure} git-version @var{VERSION} @var{REVISION} @var{COMMIT}
+Return the version string for packages using @code{git-fetch}.
+
+@lisp
+(git-version "0.2.3" "0" "93818c936ee7e2f1ba1b315578bde363a7d43d05")
+@result{} "0.2.3-0.93818c9"
+@end lisp
+@end deffn
+
+@deffn {Scheme Procedure} hg-version @var{VERSION} @var{REVISION} @var{CHANGESET}
+Return the version string for packages using @code{hg-fetch}. It works
+in the same way as @code{git-version}.
+@end deffn
+
@node Synopses and Descriptions
@subsection Synopses and Descriptions
@@ -89,6 +89,7 @@ Copyright @copyright{} 2020 Jonathan Brielmaier@*
Copyright @copyright{} 2020 Edgar Vincent@*
Copyright @copyright{} 2021 Maxime Devos@*
Copyright @copyright{} 2021 B. Wilson@*
+Copyright @copyright{} 2021 Xinglu Chen@*
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -6657,7 +6658,8 @@ This is the data type representing a package recipe.
The name of the package, as a string.
@item @code{version}
-The version of the package, as a string.
+The version of the package, as a string. @xref{Version Numbers}, for
+guidelines.
@item @code{source}
An object telling how the source code for the package should be