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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/guix.texi | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index 32bfd29dbe..9cb7ac53f9 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -6817,6 +6817,30 @@ cross-compiling: It is an error to refer to @code{this-package} outside a package definition. @end deffn +The following helper procedures are provided to help deal with package +inputs. + +@deffn {Scheme Procedure} lookup-package-input @var{package} @var{name} +@deffnx {Scheme Procedure} lookup-package-native-input @var{package} @var{name} +@deffnx {Scheme Procedure} lookup-package-propagated-input @var{package} @var{name} +@deffnx {Scheme Procedure} lookup-package-direct-input @var{package} @var{name} +Look up @var{name} among @var{package}'s inputs (or native, propagated, +or direct inputs). Return it if found, @code{#f} otherwise. + +@var{name} is the name of a package depended on. Here's how you might +use it: + +@lisp +(use-modules (guix packages) (gnu packages base)) + +(lookup-package-direct-input coreutils "gmp") +@result{} #<package gmp@@6.2.1 @dots{}> +@end lisp + +In this example we obtain the @code{gmp} package that is among the +direct inputs of @code{coreutils}. +@end deffn + Because packages are regular Scheme objects that capture a complete dependency graph and associated build procedures, it is often useful to write procedures that take a package and return a modified version |