Fix sx-tag-filter

It wasn't returning any .items because it wasn't included in the
filter.  This commit also introduces a convenience macro in sx-filter to
avoid this scenario in the future.

2 files changed, 37 insertions, 2 deletions

diff --git a/sx-filter.el b/sx-filter.el
index 8c00c12..ad37e67 100644
--- a/sx-filter.el
+++ b/sx-filter.el
@@ -41,7 +41,40 @@ Structure:
      ...)")
 
 
-;;; Compilation
+;;; Creation
+
+(defmacro sx-filter-from-nil (included)
+  "Creates a filter data structure with INCLUDED fields.
+All wrapper fields are included by default."
+  ;; @OTODO: it would be neat to have syntax like
+  ;; 
+  ;; (field-a
+  ;;  field-b
+  ;;  (object-a subfield)
+  ;;  field-c
+  ;;  (object-b subfield-a subfield-b))
+  ;;
+  ;; expand into
+  ;;
+  ;; (field-a
+  ;;  field-b
+  ;;  object-a.subfield
+  ;;  field-c
+  ;;  object-b.subfield-a object-b.subfield-b)
+  `(quote ((,@included
+            .backoff
+            .error_id
+            .error_message
+            .error_name
+            .has_more
+            .items
+            .page
+            .page_size
+            .quota_max
+            .quota_remaining
+            .total
+            .type)
+           nil none)))
 
 ;;; @TODO allow BASE to be a precompiled filter name
 (defun sx-filter-compile (&optional include exclude base)
diff --git a/sx-tag.el b/sx-tag.el
index 511c474..9f8a5a9 100644
--- a/sx-tag.el
+++ b/sx-tag.el
@@ -26,7 +26,9 @@
 
 
 ;;; Getting the list from a site
-(defvar sx-tag-filter '((tag.name))
+(defvar sx-tag-filter
+  (sx-filter-from-nil
+   (tag.name))
   "Filter used when querying tags.")
 
 (defun sx-tag--get-some-tags-containing (site string)