import: Add Elm importer.

* guix/import/elm.scm, guix/scripts/import/elm.scm: New files.
* Makefile.am (MODULES): Add them.
* guix/scripts/import.scm (importers): Add "elm".
* doc/guix.texi (Invoking guix import): Document Elm importer.
* doc/contributing.texi (Elm Packages): Mention it.
* tests/elm.scm ("(guix import elm)"): New test group.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

1 files changed, 171 insertions, 0 deletions

diff --git a/tests/elm.scm b/tests/elm.scm
index 96f958f060..c30623da03 100644
--- a/tests/elm.scm
+++ b/tests/elm.scm
@@ -18,6 +18,13 @@
 
 (define-module (test-elm)
   #:use-module (guix build-system elm)
+  #:use-module (guix import elm)
+  #:use-module (guix base32)
+  #:use-module (guix hash)
+  #:use-module (guix utils)
+  #:autoload   (gcrypt hash) (hash-algorithm sha256)
+  #:use-module (json)
+  #:use-module (ice-9 match)
   #:use-module (srfi srfi-64))
 
 (test-begin "elm")
@@ -94,4 +101,168 @@
     (test-not-inferred "gcc-toolchain")
     (test-not-inferred "font-adobe-source-sans-pro")))
 
+(define test-package-registry-json
+  ;; we intentionally list versions in different orders here
+  "{
+    \"elm/core\": [\"1.0.0\", \"1.0.1\", \"1.0.2\", \"1.0.3\", \"1.0.4\"],
+    \"elm-guix/demo\": [\"2.0.0\", \"3.0.0\", \"1.0.0\"]
+}")
+
+(define test-elm-core-json
+  "{
+    \"type\": \"package\",
+    \"name\": \"elm/core\",
+    \"summary\": \"Elm's standard libraries\",
+    \"license\": \"BSD-3-Clause\",
+    \"version\": \"1.0.4\",
+    \"exposed-modules\": {
+        \"Primitives\": [
+            \"Basics\",
+            \"String\",
+            \"Char\",
+            \"Bitwise\",
+            \"Tuple\"
+        ],
+        \"Collections\": [
+            \"List\",
+            \"Dict\",
+            \"Set\",
+            \"Array\"
+        ],
+        \"Error Handling\": [
+            \"Maybe\",
+            \"Result\"
+        ],
+        \"Debug\": [
+            \"Debug\"
+        ],
+        \"Effects\": [
+            \"Platform.Cmd\",
+            \"Platform.Sub\",
+            \"Platform\",
+            \"Process\",
+            \"Task\"
+        ]
+    },
+    \"elm-version\": \"0.19.0 <= v < 0.20.0\",
+    \"dependencies\": {},
+    \"test-dependencies\": {}
+}")
+
+(define test-elm-core-readme
+  "# Core Libraries
+
+Every Elm project needs this package!
+
+It provides **basic functionality** like addition and subtraction as well as
+**data structures** like lists, dictionaries, and sets.")
+
+(define test-elm-guix-demo-json
+  "{
+    \"type\": \"package\",
+    \"name\": \"elm-guix/demo\",
+    \"summary\": \"A test for `(guix import elm)`\",
+    \"license\": \"GPL-3.0-or-later\",
+    \"version\": \"3.0.0\",
+    \"exposed-modules\": [
+        \"Guix.Demo\"
+    ],
+    \"elm-version\": \"0.19.0 <= v < 0.20.0\",
+    \"dependencies\": {
+        \"elm/core\": \"1.0.0 <= v < 2.0.0\"
+    },
+    \"test-dependencies\": {
+        \"elm/json\": \"1.0.0 <= v < 2.0.0\"
+    }
+}")
+
+(define test-elm-guix-demo-readme
+  ;; intentionally left blank
+  "")
+
+(define (directory-sha256 directory)
+  "Returns the string representing the hash of DIRECTORY as would be used in a
+package definition."
+  (bytevector->nix-base32-string
+   (file-hash* directory
+               #:algorithm (hash-algorithm sha256)
+               #:recursive? #t)))
+
+(test-group "(guix import elm)"
+  (call-with-temporary-directory
+   (lambda (dir)
+     ;; Initialize our fake git checkouts.
+     (define elm-core-dir
+       (string-append dir "/test-elm-core-1.0.4"))
+     (define elm-guix-demo-dir
+       (string-append dir "/test-elm-guix-demo-3.0.0"))
+     (for-each (match-lambda
+                 ((dir json readme)
+                  (mkdir dir)
+                  (with-output-to-file (string-append dir "/elm.json")
+                    (lambda ()
+                      (display json)))
+                  (with-output-to-file (string-append dir "/README.md")
+                    (lambda ()
+                      (display readme)))))
+               `((,elm-core-dir ,test-elm-core-json ,test-elm-core-readme)
+                 (,elm-guix-demo-dir
+                  ,test-elm-guix-demo-json
+                  ,test-elm-guix-demo-readme)))
+     ;; Replace network resources with sample data.
+     (parameterize ((%elm-package-registry
+                     (lambda ()
+                       (json-string->scm test-package-registry-json)))
+                    (%current-elm-checkout
+                     (lambda (name version)
+                       (match (list name version)
+                         (("elm/core" "1.0.4")
+                          elm-core-dir)
+                         (("elm-guix/demo" "3.0.0")
+                          elm-guix-demo-dir)))))
+       (test-assert "(elm->guix-package \"elm/core\")"
+         (match (elm->guix-package "elm/core")
+           (`(package
+               (name "elm-core")
+               (version "1.0.4")
+               (source (elm-package-origin
+                        "elm/core"
+                        version
+                        (base32 ,(? string? hash))))
+               (build-system elm-build-system)
+               (home-page
+                "https://package.elm-lang.org/packages/elm/core/1.0.4")
+               (synopsis "Elm's standard libraries")
+               (description "Every Elm project needs this package!")
+               (license license:bsd-3))
+            (equal? (directory-sha256 elm-core-dir)
+                    hash))
+           (x
+            (raise-exception x))))
+       (test-assert "(elm-recursive-import \"elm-guix/demo\")"
+         (match (elm-recursive-import "elm-guix/demo")
+           (`((package
+                (name "elm-guix-demo")
+                (version "3.0.0")
+                (source (elm-package-origin
+                         "elm-guix/demo"
+                         version
+                         (base32 ,(? string? hash))))
+                (build-system elm-build-system)
+                (propagated-inputs
+                 ,'`(("elm-core" ,elm-core)))
+                (inputs
+                 ,'`(("elm-json" ,elm-json)))
+                (home-page
+                 "https://package.elm-lang.org/packages/elm-guix/demo/3.0.0")
+                (synopsis "A test for `(guix import elm)`")
+                (description
+                 "This package provides a test for `(guix import elm)`")
+                (properties '((upstream-name . "elm-guix/demo")))
+                (license license:gpl3+)))
+            (equal? (directory-sha256 elm-guix-demo-dir)
+                    hash))
+           (x
+            (raise-exception x))))))))
+
 (test-end "elm")