guix: toml: Fix evaluation of empty inline tables.

* guix/build/toml.scm (eval-toml-file): Add pattern for empty inline table.
* tests/toml.scm ("parse-toml: Empty inline table"): New testcase.

Change-Id: I69663af2a861716acfb801fad4474e029e102a1b

guix/build/toml.scm

@@ -414,6 +414,7 @@ the list KEY. For instance a KEY (a b) would retrieve alist[a][b]."
                                           local-time)
                                         tails)))
       ('array (list))
+      ('inline-table '())
       (('inline-table tails ...)
        (eval (keyword-flatten '(keyval) tails) '() '()))))
 

tests/toml.scm

@@ -396,6 +396,14 @@ fruit.apple.taste.sweet = true"))
 point = { x = 1, y = 2 }
 animal = { type.name = \"pug\" }"))
 
+(test-equal "parse-toml: Empty inline table"
+ '(("name")
+   ("point")
+   ("animal"))
+ (parse-toml "name = {}
+point = { }
+animal = {    }"))
+
 (test-error "parse-toml: Invalid assignment to inline table"
  #t
  (parse-toml "[product]