scripts: Add --list-systems and --list-targets options.

Also factorize the --system and --target build options. Check that the passed
system and target arguments are known platforms.

* doc/guix.texi (Additional Build Options): Document the new --list-systems
and --list-targets options.
* guix/scripts/build.scm (show-cross-build-options-help,
show-emulated-build-options-help, list-systems, list-targets): New procedures.
(%standard-cross-build-options, %standard-emulated-build-options): New
variables.
(show-help): Remove --system and --target entries and use
show-cross-build-options-help and show-emulated-build-options-help procedures instead.
(%options): Remove --system and --target entries and use
%standard-cross-build-options and %standard-emulated-build-options variables instead.
* guix/scripts/archive.scm (show-help, %options): Adapt them.
* guix/scripts/environment.scm: Ditto.
* guix/scripts/graph.scm: Ditto.
* guix/scripts/pack.scm: Ditto.
* guix/scripts/pull.scm: Ditto.
* guix/scripts/size.scm: Ditto.
* guix/scripts/weather.scm: Ditto.

Signed-off-by: Mathieu Othacehe <othacehe@gnu.org>

9 files changed, 120 insertions, 74 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 9cdee15d55..761fceb9c3 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -12397,6 +12397,14 @@ Cross-build for @var{triplet}, which must be a valid GNU triplet, such
 as @code{"aarch64-linux-gnu"} (@pxref{Specifying Target Triplets, GNU
 configuration triplets,, autoconf, Autoconf}).
 
+@item --list-systems
+List all the supported systems, that can be passed as an argument to
+@option{--system}.
+
+@item --list-targets
+List all the supported targets, that can be passed as an argument to
+@option{--target}.
+
 @anchor{build-check}
 @item --check
 @cindex determinism, checking
diff --git a/guix/scripts/archive.scm b/guix/scripts/archive.scm
index f8678aa5f9..1e961c84e6 100644
--- a/guix/scripts/archive.scm
+++ b/guix/scripts/archive.scm
@@ -93,14 +93,14 @@ Export/import one or more packages from/to the store.\n"))
   (display (G_ "
   -S, --source           build the packages' source derivations"))
   (display (G_ "
-  -s, --system=SYSTEM    attempt to build for SYSTEM--e.g., \"i686-linux\""))
-  (display (G_ "
-      --target=TRIPLET   cross-build for TRIPLET--e.g., \"armel-linux-gnu\""))
-  (display (G_ "
   -v, --verbosity=LEVEL  use the given verbosity LEVEL"))
 
   (newline)
   (show-build-options-help)
+  (newline)
+  (show-cross-build-options-help)
+  (newline)
+  (show-native-build-options-help)
 
   (newline)
   (display (G_ "
@@ -166,14 +166,6 @@ Export/import one or more packages from/to the store.\n"))
          (option '(#\S "source") #f #f
                  (lambda (opt name arg result)
                    (alist-cons 'source? #t result)))
-         (option '(#\s "system") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'system arg
-                               (alist-delete 'system result eq?))))
-         (option '("target") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'target arg
-                               (alist-delete 'target result eq?))))
          (option '(#\e "expression") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'expression arg result)))
@@ -186,7 +178,9 @@ Export/import one or more packages from/to the store.\n"))
                  (lambda (opt name arg result)
                    (alist-cons 'dry-run? #t result)))
 
-         %standard-build-options))
+         (append %standard-build-options
+                 %standard-cross-build-options
+                 %standard-native-build-options)))
 
 (define (derivation-from-expression store str package-derivation
                                     system source?)
diff --git a/guix/scripts/build.scm b/guix/scripts/build.scm
index d9cdb6e5e0..a09c54451f 100644
--- a/guix/scripts/build.scm
+++ b/guix/scripts/build.scm
@@ -47,6 +47,7 @@
   #:use-module (srfi srfi-35)
   #:use-module (srfi srfi-37)
   #:use-module (gnu packages)
+  #:use-module (gnu platform)
   #:use-module ((guix status) #:select (with-status-verbosity))
   #:use-module ((guix progress) #:select (current-terminal-columns))
   #:use-module ((guix build syscalls) #:select (terminal-columns))
@@ -54,9 +55,15 @@
   #:export (log-url
 
             %standard-build-options
+            %standard-cross-build-options
+            %standard-native-build-options
+
             set-build-options-from-command-line
             set-build-options-from-command-line*
+
             show-build-options-help
+            show-cross-build-options-help
+            show-native-build-options-help
 
             guix-build
             register-root
@@ -184,6 +191,18 @@ options handled by 'set-build-options-from-command-line', and listed in
   (display (G_ "
       --debug=LEVEL      produce debugging output at LEVEL")))
 
+(define (show-cross-build-options-help)
+  (display (G_ "
+      --list-targets     list available targets"))
+  (display (G_ "
+      --target=TRIPLET   cross-build for TRIPLET--e.g., \"aarch64-linux-gnu\"")))
+
+(define (show-native-build-options-help)
+  (display (G_ "
+      --list-systems     list available systems"))
+  (display (G_ "
+  -s, --system=SYSTEM    attempt to build for SYSTEM--e.g., \"i686-linux\"")))
+
 (define (set-build-options-from-command-line store opts)
   "Given OPTS, an alist as returned by 'args-fold' given
 '%standard-build-options', set the corresponding build options on STORE."
@@ -319,6 +338,52 @@ use '--no-offload' instead~%")))
                         (leave (G_ "not a number: '~a' option argument: ~a~%")
                                name arg)))))))
 
+(define (list-systems)
+  "Print the available systems."
+  (display (G_ "The available systems are:\n"))
+  (newline)
+  (format #t "~{   - ~a ~%~}"
+          (sort (systems) string<?)))
+
+(define (list-targets)
+  "Print the available targets."
+  (display (G_ "The available targets are:\n"))
+  (newline)
+  (format #t "~{   - ~a ~%~}"
+          (sort (targets) string<?)))
+
+(define %standard-cross-build-options
+  ;; Build options related to cross builds.
+  (list
+   (option '("list-targets") #f #f
+           (lambda (opt name arg result)
+             (list-targets)
+             (exit 0)))
+   (option '("target") #t #f
+           (lambda (opt name arg result . rest)
+             (let ((t (false-if-exception
+                       (first (member arg (targets))))))
+               (if t
+                   (apply values (alist-cons 'target t result) rest)
+                   (leave (G_ "'~a' is not a supported target~%")
+                          arg)))))))
+
+(define %standard-native-build-options
+  ;; Build options related to native builds.
+  (list
+   (option '("list-systems") #f #f
+           (lambda (opt name arg result)
+             (list-systems)
+             (exit 0)))
+   (option '(#\s "system") #t #f
+           (lambda (opt name arg result . rest)
+             (let ((s (false-if-exception
+                       (first (member arg (systems))))))
+               (if s
+                   (apply values (alist-cons 'system s result) rest)
+                   (leave (G_ "'~a' is not a supported system~%")
+                          arg)))))))
+
 
 ;;;
 ;;; Command-line options.
@@ -353,10 +418,6 @@ Build the given PACKAGE-OR-DERIVATION and return their output paths.\n"))
       --sources[=TYPE]   build source derivations; TYPE may optionally be one
                          of \"package\", \"all\" (default), or \"transitive\""))
   (display (G_ "
-  -s, --system=SYSTEM    attempt to build for SYSTEM--e.g., \"i686-linux\""))
-  (display (G_ "
-      --target=TRIPLET   cross-build for TRIPLET--e.g., \"armel-linux-gnu\""))
-  (display (G_ "
   -d, --derivations      return the derivation paths of the given packages"))
   (display (G_ "
       --check            rebuild items to check for non-determinism issues"))
@@ -374,6 +435,10 @@ Build the given PACKAGE-OR-DERIVATION and return their output paths.\n"))
   (newline)
   (show-build-options-help)
   (newline)
+  (show-cross-build-options-help)
+  (newline)
+  (show-native-build-options-help)
+  (newline)
   (show-transformation-options-help)
   (newline)
   (display (G_ "
@@ -420,13 +485,6 @@ must be one of 'package', 'all', or 'transitive'~%")
                           (alist-cons 'build-mode (build-mode repair)
                                       result)
                           rest)))
-         (option '(#\s "system") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'system arg result)))
-         (option '("target") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'target arg
-                               (alist-delete 'target result eq?))))
          (option '(#\d "derivations") #f #f
                  (lambda (opt name arg result)
                    (alist-cons 'derivations-only? #t result)))
@@ -459,7 +517,9 @@ must be one of 'package', 'all', or 'transitive'~%")
                    (alist-cons 'log-file? #t result)))
 
          (append %transformation-options
-                 %standard-build-options)))
+                 %standard-build-options
+                 %standard-cross-build-options
+                 %standard-native-build-options)))
 
 (define (options->things-to-build opts)
   "Read the arguments from OPTS and return a list of high-level objects to
diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
index 07b54cd89b..3216235937 100644
--- a/guix/scripts/environment.scm
+++ b/guix/scripts/environment.scm
@@ -96,8 +96,6 @@ shell'."
   (display (G_ "
       --search-paths     display needed environment variable definitions"))
   (display (G_ "
-  -s, --system=SYSTEM    attempt to build for SYSTEM--e.g., \"i686-linux\""))
-  (display (G_ "
   -r, --root=FILE        make FILE a symlink to the result, and register it
                          as a garbage collector root"))
   (display (G_ "
@@ -145,6 +143,8 @@ COMMAND or an interactive shell in that environment.\n"))
   (newline)
   (show-build-options-help)
   (newline)
+  (show-native-build-options-help)
+  (newline)
   (show-transformation-options-help)
   (newline)
   (display (G_ "
@@ -226,10 +226,6 @@ use '--preserve' instead~%"))
          (option '(#\n "dry-run") #f #f
                  (lambda (opt name arg result)
                    (alist-cons 'dry-run? #t result)))
-         (option '(#\s "system") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'system arg
-                               (alist-delete 'system result eq?))))
          (option '(#\C "container") #f #f
                  (lambda (opt name arg result)
                    (alist-cons 'container? #t result)))
@@ -273,7 +269,8 @@ use '--preserve' instead~%"))
                    (alist-cons 'bootstrap? #t result)))
 
          (append %transformation-options
-                 %standard-build-options)))
+                 %standard-build-options
+                 %standard-native-build-options)))
 
 (define (pick-all alist key)
   "Return a list of values in ALIST associated with KEY."
diff --git a/guix/scripts/graph.scm b/guix/scripts/graph.scm
index 535875c858..2f102180c9 100644
--- a/guix/scripts/graph.scm
+++ b/guix/scripts/graph.scm
@@ -39,7 +39,9 @@
                           options->transformation
                           %transformation-options))
   #:use-module ((guix scripts build)
-                #:select (%standard-build-options))
+                #:select (%standard-build-options
+                          %standard-native-build-options
+                          show-native-build-options-help))
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
   #:use-module (srfi srfi-34)
@@ -504,10 +506,6 @@ package modules, while attempting to retain user package modules."
          (option '(#\e "expression") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'expression arg result)))
-         (option '(#\s "system") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'system arg
-                               (alist-delete 'system result eq?))))
          (find (lambda (option)
                 (member "load-path" (option-names option)))
               %standard-build-options)
@@ -519,7 +517,8 @@ package modules, while attempting to retain user package modules."
                  (lambda args
                    (show-version-and-exit "guix graph")))
 
-         %transformation-options))
+         (append %transformation-options
+                 %standard-native-build-options)))
 
 (define (show-help)
   ;; TRANSLATORS: Here 'dot' is the name of a program; it must not be
@@ -540,8 +539,6 @@ Emit a representation of the dependency graph of PACKAGE...\n"))
       --path             display the shortest path between the given nodes"))
   (display (G_ "
   -e, --expression=EXPR  consider the package EXPR evaluates to"))
-  (display (G_ "
-  -s, --system=SYSTEM    consider the graph for SYSTEM--e.g., \"i686-linux\""))
   (newline)
   (display (G_ "
   -L, --load-path=DIR    prepend DIR to the package module search path"))
@@ -553,6 +550,8 @@ Emit a representation of the dependency graph of PACKAGE...\n"))
   (display (G_ "
   -V, --version          display version information and exit"))
   (newline)
+  (show-native-build-options-help)
+  (newline)
   (show-bug-report-information))
 
 (define %default-options
diff --git a/guix/scripts/pack.scm b/guix/scripts/pack.scm
index 32f0d3abb1..d3ee69840c 100644
--- a/guix/scripts/pack.scm
+++ b/guix/scripts/pack.scm
@@ -1244,17 +1244,9 @@ last resort for relocation."
          (option '(#\m "manifest") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'manifest arg result)))
-         (option '(#\s "system") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'system arg
-                               (alist-delete 'system result eq?))))
          (option '("entry-point") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'entry-point arg result)))
-         (option '("target") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'target arg
-                               (alist-delete 'target result eq?))))
          (option '(#\C "compression") #t #f
                  (lambda (opt name arg result)
                    (alist-cons 'compressor (lookup-compressor arg)
@@ -1305,13 +1297,19 @@ last resort for relocation."
 
          (append %deb-format-options
                  %transformation-options
-                 %standard-build-options)))
+                 %standard-build-options
+                 %standard-cross-build-options
+                 %standard-native-build-options)))
 
 (define (show-help)
   (display (G_ "Usage: guix pack [OPTION]... PACKAGE...
 Create a bundle of PACKAGE.\n"))
   (show-build-options-help)
   (newline)
+  (show-cross-build-options-help)
+  (newline)
+  (show-native-build-options-help)
+  (newline)
   (show-transformation-options-help)
   (newline)
   (show-deb-format-options)
@@ -1325,10 +1323,6 @@ Create a bundle of PACKAGE.\n"))
   (display (G_ "
   -e, --expression=EXPR  consider the package EXPR evaluates to"))
   (display (G_ "
-  -s, --system=SYSTEM    attempt to build for SYSTEM--e.g., \"i686-linux\""))
-  (display (G_ "
-      --target=TRIPLET   cross-build for TRIPLET--e.g., \"armel-linux-gnu\""))
-  (display (G_ "
   -C, --compression=TOOL compress using TOOL--e.g., \"lzip\""))
   (display (G_ "
   -S, --symlink=SPEC     create symlinks to the profile according to SPEC"))
diff --git a/guix/scripts/pull.scm b/guix/scripts/pull.scm
index 8eb9b31288..f01764637b 100644
--- a/guix/scripts/pull.scm
+++ b/guix/scripts/pull.scm
@@ -117,11 +117,12 @@ Download and deploy the latest version of Guix.\n"))
   (display (G_ "
   -v, --verbosity=LEVEL  use the given verbosity LEVEL"))
   (display (G_ "
-  -s, --system=SYSTEM    attempt to build for SYSTEM--e.g., \"i686-linux\""))
-  (display (G_ "
       --bootstrap        use the bootstrap Guile to build the new Guix"))
   (newline)
   (show-build-options-help)
+  (newline)
+  (show-native-build-options-help)
+  (newline)
   (display (G_ "
   -h, --help             display this help and exit"))
   (display (G_ "
@@ -182,10 +183,6 @@ Download and deploy the latest version of Guix.\n"))
                  (lambda (opt name arg result)
                    (alist-cons 'profile (canonicalize-profile arg)
                                result)))
-         (option '(#\s "system") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'system arg
-                               (alist-delete 'system result eq?))))
          (option '(#\n "dry-run") #f #f
                  (lambda (opt name arg result)
                    (alist-cons 'dry-run? #t result)))
@@ -206,7 +203,8 @@ Download and deploy the latest version of Guix.\n"))
                  (lambda args
                    (show-version-and-exit "guix pull")))
 
-         %standard-build-options))
+         (append %standard-build-options
+                 %standard-native-build-options)))
 
 (define (warn-about-backward-updates channel start commit relation)
   "Warn about non-forward updates of CHANNEL from START to COMMIT, without
diff --git a/guix/scripts/size.scm b/guix/scripts/size.scm
index e46983382a..5bb970443c 100644
--- a/guix/scripts/size.scm
+++ b/guix/scripts/size.scm
@@ -235,8 +235,6 @@ Report the size of the PACKAGE or STORE-ITEM, with its dependencies.\n"))
   (display (G_ "
       --substitute-urls=URLS
                          fetch substitute from URLS if they are authorized"))
-  (display (G_ "
-  -s, --system=SYSTEM    consider packages for SYSTEM--e.g., \"i686-linux\""))
   ;; TRANSLATORS: "closure" and "self" must not be translated.
   (display (G_ "
       --sort=KEY         sort according to KEY--\"closure\" or \"self\""))
@@ -251,15 +249,13 @@ Report the size of the PACKAGE or STORE-ITEM, with its dependencies.\n"))
   (display (G_ "
   -V, --version          display version information and exit"))
   (newline)
+  (show-native-build-options-help)
+  (newline)
   (show-bug-report-information))
 
 (define %options
   ;; Specifications of the command-line options.
-  (list (option '(#\s "system") #t #f
-                (lambda (opt name arg result)
-                  (alist-cons 'system arg
-                              (alist-delete 'system result eq?))))
-        (option '("substitute-urls") #t #f
+  (cons* (option '("substitute-urls") #t #f
                 (lambda (opt name arg result . rest)
                   (apply values
                          (alist-cons 'substitute-urls
@@ -287,7 +283,8 @@ Report the size of the PACKAGE or STORE-ITEM, with its dependencies.\n"))
                   (exit 0)))
         (option '(#\V "version") #f #f
                 (lambda args
-                  (show-version-and-exit "guix size")))))
+                  (show-version-and-exit "guix size")))
+        %standard-native-build-options))
 
 (define %default-options
   `((system . ,(%current-system))
diff --git a/guix/scripts/weather.scm b/guix/scripts/weather.scm
index adba614b8c..b7d8165262 100644
--- a/guix/scripts/weather.scm
+++ b/guix/scripts/weather.scm
@@ -40,6 +40,7 @@
   #:use-module (guix ci)
   #:use-module (guix sets)
   #:use-module (guix graph)
+  #:use-module (guix scripts build)
   #:autoload   (guix scripts graph) (%bag-node-type)
   #:use-module (gnu packages)
   #:use-module (web uri)
@@ -339,18 +340,18 @@ Report the availability of substitutes.\n"))
                          COUNT dependents"))
   (display (G_ "
       --display-missing  display the list of missing substitutes"))
-  (display (G_ "
-  -s, --system=SYSTEM    consider substitutes for SYSTEM--e.g., \"i686-linux\""))
   (newline)
   (display (G_ "
   -h, --help             display this help and exit"))
   (display (G_ "
   -V, --version          display version information and exit"))
   (newline)
+  (show-native-build-options-help)
+  (newline)
   (show-bug-report-information))
 
 (define %options
-  (list  (option '(#\h "help") #f #f
+  (cons* (option '(#\h "help") #f #f
                  (lambda args
                    (show-help)
                    (exit 0)))
@@ -380,9 +381,7 @@ Report the availability of substitutes.\n"))
          (option '("display-missing") #f #f
                  (lambda (opt name arg result)
                    (alist-cons 'display-missing? #t result)))
-         (option '(#\s "system") #t #f
-                 (lambda (opt name arg result)
-                   (alist-cons 'system arg result)))))
+         %standard-native-build-options))
 
 (define %default-options
   `((substitute-urls . ,%default-substitute-urls)))