[PATCH v3 0/8] emacs: JSON-based search cleanups

[Austin Clements]

This version swaps out the notmuch-search-do-results macro for a
higher-order function, notmuch-search-foreach-result.  This requires
less squiting to understand and clearly distinguishes the arguments
passed in to the function from the arguments passed to the callback.
This version also updates the docstring for
notmuch-search-result-format to mention that multi-line result formats
work and how to enter them, and it adds a NEWS patch.

Diff from v2:

diff --git a/NEWS b/NEWS
index a1a6e93..7b33f0d 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,20 @@ Maildir tag synchronization
 Emacs Interface
 ---------------
 
+Search results now get re-colored when tags are updated
+
+The formatting of tags in search results can now be customized
+
+  Previously, attempting to change the format of tags in
+  `notmuch-search-result-format` would usually break tagging from
+  search-mode.  We no longer make assumptions about the format.
+
+Multi-line search result formats are now supported
+
+  It is now possible to embed newlines in
+  `notmuch-search-result-format` to make individual search results
+  span multiple lines.
+
 Search now uses the JSON format internally
 
   This should address problems with unusual characters in authors and
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index 7302fa7..ec760dc 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -69,7 +69,13 @@
 	date, count, authors, subject, tags
 For example:
 	(setq notmuch-search-result-format \(\(\"authors\" . \"%-40s\"\)
-					     \(\"subject\" . \"%s\"\)\)\)"
+					     \(\"subject\" . \"%s\"\)\)\)
+Line breaks are permitted in format strings.  Note that a line
+break at the end of an \"authors\" field will get elided if the
+authors list is long; place it instead at the beginning of the
+following field.  To enter a line break when setting this
+variable with setq, use \\n.  To enter a line break in customize,
+press \\[quoted-insert] C-j."
   :type '(alist :key-type (string) :value-type (string))
   :group 'notmuch-search)
 
@@ -433,32 +439,39 @@ returns nil"
     (next-single-property-change (or pos (point)) 'notmuch-search-result
 				 nil (point-max))))
 
-(defmacro notmuch-search-do-results (beg end pos-sym &rest body)
-  "Invoke BODY for each result between BEG and END.
-
-POS-SYM will be bound to the point at the beginning of the
-current result."
-  (declare (indent 3))
-  (let ((end-sym (make-symbol "end"))
-	(first-sym (make-symbol "first")))
-    `(let ((,pos-sym (notmuch-search-result-beginning ,beg))
-	   ;; End must be a marker in case body changes the text
-	   (,end-sym (copy-marker ,end))
-	   ;; Make sure we examine one result, even if (= beg end)
-	   (,first-sym t))
-       ;; We have to be careful if the region extends beyond the
-       ;; results.  In this case, pos could be null or there could be
-       ;; no result at pos.
-       (while (and ,pos-sym (or (< ,pos-sym ,end-sym) ,first-sym))
-	 (when (notmuch-search-get-result ,pos-sym)
-	   , at body)
-	 (setq ,pos-sym (notmuch-search-result-end ,pos-sym)
-	       ,first-sym nil)))))
+(defun notmuch-search-foreach-result (beg end function)
+  "Invoke FUNCTION for each result between BEG and END.
+
+FUNCTION should take one argument.  It will be applied to the
+character position of the beginning of each result that overlaps
+the region between points BEG and END.  As a special case, if (=
+BEG END), FUNCTION will be applied to the result containing point
+BEG."
+
+  (lexical-let ((pos (notmuch-search-result-beginning beg))
+		;; End must be a marker in case function changes the
+		;; text.
+		(end (copy-marker end))
+		;; Make sure we examine at least one result, even if
+		;; (= beg end).
+		(first t))
+    ;; We have to be careful if the region extends beyond the results.
+    ;; In this case, pos could be null or there could be no result at
+    ;; pos.
+    (while (and pos (or (< pos end) first))
+      (when (notmuch-search-get-result pos)
+	(funcall function pos))
+      (setq pos (notmuch-search-result-end pos)
+	    first nil))))
+;; Unindent the function argument of notmuch-search-foreach-result so
+;; the indentation of callers doesn't get out of hand.
+(put 'notmuch-search-foreach-result 'lisp-indent-function 2)
 
 (defun notmuch-search-properties-in-region (property beg end)
   (let (output)
-    (notmuch-search-do-results beg end pos
-      (push (plist-get (notmuch-search-get-result pos) property) output))
+    (notmuch-search-foreach-result beg end
+      (lambda (pos)
+	(push (plist-get (notmuch-search-get-result pos) property) output)))
     output))
 
 (defun notmuch-search-find-thread-id ()
@@ -542,18 +555,20 @@ and will also appear in a buffer named \"*Notmuch errors*\"."
 
 (defun notmuch-search-get-tags-region (beg end)
   (let (output)
-    (notmuch-search-do-results beg end pos
-      (setq output (append output (notmuch-search-get-tags pos))))
+    (notmuch-search-foreach-result beg end
+      (lambda (pos)
+	(setq output (append output (notmuch-search-get-tags pos)))))
     output))
 
 (defun notmuch-search-tag-region (beg end &optional tag-changes)
   "Change tags for threads in the given region."
   (let ((search-string (notmuch-search-find-thread-id-region-search beg end)))
     (setq tag-changes (funcall 'notmuch-tag search-string tag-changes))
-    (notmuch-search-do-results beg end pos
-      (notmuch-search-set-tags
-       (notmuch-update-tags (notmuch-search-get-tags pos) tag-changes)
-       pos))))
+    (notmuch-search-foreach-result beg end
+      (lambda (pos)
+	(notmuch-search-set-tags
+	 (notmuch-update-tags (notmuch-search-get-tags pos) tag-changes)
+	 pos)))))
 
 (defun notmuch-search-tag (&optional tag-changes)
   "Change tags for the currently selected thread or region.