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Diffstat (limited to 'doc/guix.texi')
| -rw-r--r-- | doc/guix.texi | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index 3b5078741d..77bdaa50eb 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -5064,6 +5064,23 @@ headers, which comes in handy in this case: @dots{}))) @end example +@cindex extensions, for gexps +@findex with-extensions +In the same vein, sometimes you want to import not just pure-Scheme +modules, but also ``extensions'' such as Guile bindings to C libraries +or other ``full-blown'' packages. Say you need the @code{guile-json} +package available on the build side, here's how you would do it: + +@example +(use-modules (gnu packages guile)) ;for 'guile-json' + +(with-extensions (list guile-json) + (gexp->derivation "something-with-json" + #~(begin + (use-modules (json)) + @dots{}))) +@end example + The syntactic form to construct gexps is summarized below. @deffn {Scheme Syntax} #~@var{exp} @@ -5147,6 +5164,18 @@ directly defined in @var{body}@dots{}, but not on those defined, say, in procedures called from @var{body}@dots{}. @end deffn +@deffn {Scheme Syntax} with-extensions @var{extensions} @var{body}@dots{} +Mark the gexps defined in @var{body}@dots{} as requiring +@var{extensions} in their build and execution environment. +@var{extensions} is typically a list of package objects such as those +defined in the @code{(gnu packages guile)} module. + +Concretely, the packages listed in @var{extensions} are added to the +load path while compiling imported modules in @var{body}@dots{}; they +are also added to the load path of the gexp returned by +@var{body}@dots{}. +@end deffn + @deffn {Scheme Procedure} gexp? @var{obj} Return @code{#t} if @var{obj} is a G-expression. @end deffn @@ -5161,6 +5190,7 @@ information about monads.) [#:hash #f] [#:hash-algo #f] @ [#:recursive? #f] [#:env-vars '()] [#:modules '()] @ [#:module-path @var{%load-path}] @ + [#:effective-version "2.2"] @ [#:references-graphs #f] [#:allowed-references #f] @ [#:disallowed-references #f] @ [#:leaked-env-vars #f] @ @@ -5181,6 +5211,9 @@ make @var{modules} available in the evaluation context of @var{exp}; the load path during the execution of @var{exp}---e.g., @code{((guix build utils) (guix build gnu-build-system))}. +@var{effective-version} determines the string to use when adding extensions of +@var{exp} (see @code{with-extensions}) to the search path---e.g., @code{"2.2"}. + @var{graft?} determines whether packages referred to by @var{exp} should be grafted when applicable. |