Add extra folding definitions for golang

Author: samrjack

ts-fold-parsers.el

@@ -123,7 +123,13 @@
 (defun ts-fold-parsers-go ()
   "Rule set for Go."
   '((block   . ts-fold-range-seq)
-    (comment . ts-fold-range-seq)))
+    (comment . ts-fold-range-seq)
+    (const_declaration . (lambda (node offset)
+                           (ts-fold-range-markers node offset "(" ")")))
+    (field_declaration_list . ts-fold-range-seq)
+    (import_spec_list . ts-fold-range-seq)
+    (interface_type . (lambda (node offset)
+                        (ts-fold-range-markers node offset "{" "}")))))
 
 (defun ts-fold-parsers-html ()
   "Rule set for HTML."

ts-fold.el

@@ -392,6 +392,28 @@ Argument OFFSET can be used to tweak the final beginning and end position."
         (end (1- (tsc-node-end-position node))))
     (ts-fold--cons-add (cons beg end) offset)))
 
+(defun ts-fold-range-markers (node offset start-seq &optional end-seq)
+  "Returns the fold range for NODE with an OFFSET where the range
+starts at the end of the first occurence of the regular expression
+START-SEQ and ends at the end of the node or the last occurence of
+the optional regular expression LAST-SEQ.
+
+
+If no occurence is found for START-SEQ or END-SEQ or the
+occurences overlap, then the range returned is nil."
+  (when start-seq
+    (let ((beg (tsc-node-start-position node))
+          (end (tsc-node-end-position node)))
+      (save-excursion
+        (when-let* ((start-position (progn (goto-char beg)
+                                           (search-forward-regexp start-seq end t)))
+                    (end-position (if end-seq
+                                      (progn (goto-char end)
+                                             (search-backward-regexp end-seq beg t))
+                                    (1- end))))
+          (unless (> start-position end-position)
+            (ts-fold--cons-add (cons start-position end-position) offset)))))))
+
 (defun ts-fold-range-line-comment (node offset prefix)
   "Define fold range for line comment.