build-system: Introduce "bags" as an intermediate representation.

* guix/build-system.scm (<build-system>)[build, cross-build]: Remove.
  [lower]: New field.
  (<bag>): New record type.
  (make-bag): New procedure.
* guix/packages.scm (bag-transitive-inputs, bag-transitive-build-inputs,
  bag-transitive-host-inputs, bag-transitive-target-inputs,
  package->bag): New procedures.
  (package-derivation): Use it; use the bag, apply its build procedure,
  etc.
  (package-cross-derivation): Likewise.
* gnu/packages/bootstrap.scm (raw-build, make-raw-bag): New procedure.
  (%bootstrap-guile): Use them.
* guix/build-system/trivial.scm (lower): New procedure.
  (trivial-build, trivial-cross-build): Remove 'source' parameter.  Pass
  INPUTS as is.
  (trivial-build-system): Adjust accordingly.
* guix/build-system/gnu.scm (%store, inputs-search-paths,
  standard-search-paths, expand-inputs, standard-inputs): Remove.
  (gnu-lower): New procedure.
  (gnu-build): Remove 'source' and #:implicit-inputs? parameters.
  Remove 'implicit-inputs' and 'implicit-search-paths' variables.  Get
  the source from INPUT-DRVS.
  (gnu-cross-build): Likewise.
  (standard-cross-packages): Remove call to 'standard-packages'.
  (standard-cross-inputs, standard-cross-search-paths): Remove.
  (gnu-build-system): Remove 'build' and 'cross-build'; add 'lower'.
* guix/build-system/cmake.scm (lower): New procedure.
  (cmake-build): Remove 'source' and #:cmake parameters.  Use INPUTS and
  SEARCH-PATHS as is.  Get the source from INPUTS.
* guix/build-system/perl.scm: Likewise.
* guix/build-system/python.scm: Likewise.
* guix/build-system/ruby.scm: Likewise.
* gnu/packages/cross-base.scm (cross-gcc): Change "cross-linux-headers"
  to "linux-headers".
  (cross-libc)[xlinux-headers]: Pass #:implicit-cross-inputs? #f.
  Likewise.  In 'propagated-inputs', change "cross-linux-headers" to
  "linux-headers".
* guix/git-download.scm (git-fetch): Use 'standard-packages' instead of
  'standard-inputs'.
* tests/builders.scm ("gnu-build-system"): Remove use of
  'build-system-builder'.
  ("gnu-build"): Remove 'source' and #:implicit-inputs? arguments to
  'gnu-build'.
* tests/packages.scm ("search paths"): Adjust to new build system API.
  ("package-cross-derivation, no cross builder"): Likewise.
* doc/guix.texi (Build Systems): Add paragraph on bags.

1 files changed, 44 insertions, 31 deletions

diff --git a/guix/build-system/perl.scm b/guix/build-system/perl.scm
index 600e597ce8..6cf8cbe13a 100644
--- a/guix/build-system/perl.scm
+++ b/guix/build-system/perl.scm
@@ -42,9 +42,33 @@
   (let ((module (resolve-interface '(gnu packages perl))))
     (module-ref module 'perl)))
 
-(define* (perl-build store name source inputs
+(define* (lower name
+                #:key source inputs native-inputs outputs target
+                (perl (default-perl))
+                #:allow-other-keys
+                #:rest arguments)
+  "Return a bag for NAME."
+  (define private-keywords
+    '(#:source #:target #:perl #:inputs #:native-inputs))
+
+  (and (not target)                               ;XXX: no cross-compilation
+       (bag
+         (name name)
+         (host-inputs `(,@(if source
+                              `(("source" ,source))
+                              '())
+                        ,@inputs
+
+                        ;; Keep the standard inputs of 'gnu-build-system'.
+                        ,@(standard-packages)))
+         (build-inputs `(("perl" ,perl)
+                         ,@native-inputs))
+         (outputs outputs)
+         (build perl-build)
+         (arguments (strip-keyword-arguments private-keywords arguments)))))
+
+(define* (perl-build store name inputs
                      #:key
-                     (perl (default-perl))
                      (search-paths '())
                      (tests? #t)
                      (parallel-build? #t)
@@ -62,20 +86,19 @@
                                 (guix build utils))))
   "Build SOURCE using PERL, and with INPUTS.  This assumes that SOURCE
 provides a `Makefile.PL' file as its build system."
-  (define perl-search-paths
-    (append (package-native-search-paths perl)
-            (standard-search-paths)))
-
   (define builder
     `(begin
        (use-modules ,@modules)
        (perl-build #:name ,name
-                   #:source ,(if (derivation? source)
-                                 (derivation->output-path source)
-                                 source)
+                   #:source ,(match (assoc-ref inputs "source")
+                               (((? derivation? source))
+                                (derivation->output-path source))
+                               ((source)
+                                source)
+                               (source
+                                source))
                    #:search-paths ',(map search-path-specification->sexp
-                                         (append perl-search-paths
-                                                 search-paths))
+                                         search-paths)
                    #:make-maker-flags ,make-maker-flags
                    #:phases ,phases
                    #:system ,system
@@ -95,27 +118,17 @@ provides a `Makefile.PL' file as its build system."
               (guile  (module-ref distro 'guile-final)))
          (package-derivation store guile system)))))
 
-  (let ((perl (package-derivation store perl system)))
-    (build-expression->derivation store name builder
-                                  #:system system
-                                  #:inputs
-                                  `(,@(if source
-                                          `(("source" ,source))
-                                          '())
-                                    ("perl" ,perl)
-                                    ,@inputs
-
-                                    ;; Keep the standard inputs of
-                                    ;; `gnu-build-system'.
-                                    ,@(standard-inputs system))
-
-                                  #:modules imported-modules
-                                  #:outputs outputs
-                                  #:guile-for-build guile-for-build)))
+  (build-expression->derivation store name builder
+                                #:system system
+                                #:inputs inputs
+                                #:modules imported-modules
+                                #:outputs outputs
+                                #:guile-for-build guile-for-build))
 
 (define perl-build-system
-  (build-system (name 'perl)
-                (description "The standard Perl build system")
-                (build perl-build)))
+  (build-system
+    (name 'perl)
+    (description "The standard Perl build system")
+    (lower lower)))
 
 ;;; perl.scm ends here