Add a 'build-status' enumeration.

* src/cuirass/utils.scm (define-enumeration): New macro.
* src/cuirass/database.scm (build-status): New macro.
* src/cuirass/base.scm (build-packages)[hydra-build-status]: Remove.
Use the 'build-status' macro instead.

src/cuirass/base.scm

@@ -290,15 +290,6 @@ and so on. "
 
 (define (build-packages store db jobs)
   "Build JOBS and return a list of Build results."
-
-  (define hydra-build-status
-    ;; Build status as expected by hydra compatible API's.
-    '((succeeded         . 0)
-      (failed            . 1)
-      (failed-dependency . 2)
-      (failed-other      . 3)
-      (cancelled         . 4)))
-
   (define (register job)
     (let* ((name     (assq-ref job #:job-name))
            (drv      (assq-ref job #:derivation))
@@ -317,8 +308,8 @@ and so on. "
                      (#:log . ,log)
                      (#:status .
                       ,(match (length outputs)
-                         (0 (assq-ref hydra-build-status 'failed))
-                         (_ (assq-ref hydra-build-status 'succeeded))))
+                         (0 (build-status failed))
+                         (_ (build-status succeeded))))
                      (#:outputs . ,outputs)
                      ;;; XXX: For now, we do not know start/stop build time.
                      (#:timestamp . ,cur-time)

src/cuirass/database.scm

@@ -37,6 +37,7 @@
             db-add-evaluation
             db-add-derivation
             db-get-derivation
+            build-status
             db-add-build
             db-get-build
             db-get-builds
@@ -197,6 +198,14 @@ string."
 (define SQLITE_CONSTRAINT_PRIMARYKEY
   (logior SQLITE_CONSTRAINT (ash 6 8)))
 
+(define-enumeration build-status
+  ;; Build status as expected by Hydra's API.
+  (succeeded         0)
+  (failed            1)
+  (failed-dependency 2)
+  (failed-other      3)
+  (cancelled         4))
+
 (define (db-add-build db build)
   "Store BUILD in database DB. BUILD eventual outputs are stored
 in the OUTPUTS table."

src/cuirass/utils.scm

@@ -1,5 +1,5 @@
 ;;; utils.scm -- helper procedures
-;;; Copyright © 2012, 2013, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012, 2013, 2016, 2018 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2015 David Thompson <davet@gnu.org>
 ;;; Copyright © 2016 Mathieu Lirzin <mthl@gnu.org>
 ;;;
@@ -24,7 +24,8 @@
   #:use-module (json)
   #:export (alist?
             object->json-scm
-            object->json-string))
+            object->json-string
+            define-enumeration))
 
 (define (alist? obj)
   "Return #t if OBJ is an alist."
@@ -47,3 +48,12 @@
 (define* (object->json-string object #:key pretty)
   "Return OBJECT as a JSON object."
   (scm->json-string (object->json-scm object) #:pretty pretty))
+
+(define-syntax-rule (define-enumeration name (symbol value) ...)
+  "Define an 'enum' type with the given SYMBOL/VALUE pairs.  NAME is defined a
+macro that accepts one of these symbols and expands to the corresponding
+value."
+  (define-syntax name
+    (syntax-rules (symbol ...)
+      ((_ symbol) value)
+      ...)))