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, 29 insertions, 16 deletions

diff --git a/guix/build-system/trivial.scm b/guix/build-system/trivial.scm
index 897c5c6152..1b07f14e63 100644
--- a/guix/build-system/trivial.scm
+++ b/guix/build-system/trivial.scm
@@ -34,42 +34,55 @@
             (guile  (module-ref distro 'guile-final)))
        (package-derivation store guile system)))))
 
-(define* (trivial-build store name source inputs
+(define* (lower name
+                #:key source inputs native-inputs outputs target
+                guile builder modules)
+  "Return a bag for NAME."
+  (bag
+    (name name)
+    (host-inputs `(,@(if source
+                         `(("source" ,source))
+                         '())
+                   ,@inputs))
+    (build-inputs native-inputs)
+    (outputs outputs)
+    (build (if target trivial-cross-build trivial-build))
+    (arguments `(#:guile ,guile
+                 #:builder ,builder
+                 #:modules ,modules))))
+
+(define* (trivial-build store name inputs
                         #:key
                         outputs guile system builder (modules '())
                         search-paths)
   "Run build expression BUILDER, an expression, for SYSTEM.  SOURCE is
 ignored."
   (build-expression->derivation store name builder
-                                #:inputs (if source
-                                             `(("source" ,source) ,@inputs)
-                                             inputs)
+                                #:inputs inputs
                                 #:system system
                                 #:outputs outputs
                                 #:modules modules
                                 #:guile-for-build
                                 (guile-for-build store guile system)))
 
-(define* (trivial-cross-build store name target source inputs native-inputs
+(define* (trivial-cross-build store name
                               #:key
+                              target native-drvs target-drvs
                               outputs guile system builder (modules '())
                               search-paths native-search-paths)
-  "Like `trivial-build', but in a cross-compilation context."
+  "Run build expression BUILDER, an expression, for SYSTEM.  SOURCE is
+ignored."
   (build-expression->derivation store name builder
+                                #:inputs (append native-drvs target-drvs)
                                 #:system system
-                                #:inputs
-                                (let ((inputs (append native-inputs inputs)))
-                                  (if source
-                                      `(("source" ,source) ,@inputs)
-                                      inputs))
                                 #:outputs outputs
                                 #:modules modules
                                 #:guile-for-build
                                 (guile-for-build store guile system)))
 
 (define trivial-build-system
-  (build-system (name 'trivial)
-                (description
-                 "Trivial build system, to run arbitrary Scheme build expressions")
-                (build trivial-build)
-                (cross-build trivial-cross-build)))
+  (build-system
+    (name 'trivial)
+    (description
+     "Trivial build system, to run arbitrary Scheme build expressions")
+    (lower lower)))