Origami for python.

Based on code published in issue
gregsexton/origami.el#69.

imenu-origami.el

@@ -0,0 +1,43 @@
+;; -*- mode: emacs-lisp-mode; lexical-binding: t -*-
+
+;; Imenu based folding for origami, per issue #[69](https://github.com/gregsexton/origami.el/issues/69)
+
+(defun origami-parser-imenu-flat (create)
+  "Origami parser producing folds for each imenu entry, without nesting."
+  (require 'imenu)
+  (lambda (content)
+    (let ((orig-major-mode major-mode))
+      (with-temp-buffer
+        (insert content)
+        (funcall orig-major-mode)
+        (let* ((items
+                (-as-> (imenu--make-index-alist t) items
+                       (-flatten items)
+                       (-filter 'listp items)))
+               (positions
+                (-as-> (-map #'cdr items) positions
+                       (-filter 'identity positions)
+                       (-map-when 'markerp 'marker-position positions)
+                       (-filter 'natnump positions)
+                       (cons (point-min) positions)
+                       (-snoc positions (point-max))
+                       (-sort '< positions)
+                       (-uniq positions)))
+               (ranges
+                (-zip-pair positions (-map '1- (cdr positions))))
+               (fold-nodes
+                (--map
+                 (-let*
+                     (((range-beg . range-end) it)
+                      (line-beg
+                       (progn (goto-char range-beg)
+                              (line-beginning-position)))
+                      (offset
+                       (- (min (line-end-position) range-end) line-beg))
+                      (fold-node
+                       (funcall create line-beg range-end offset nil)))
+                   fold-node)
+                 ranges)))
+          fold-nodes)))))
+
+(provide 'imenu-origami)