Add NERDTree statusline

powerline/config_files/config.json

@@ -37,7 +37,9 @@
 			"local_themes": {
 				"cmdwin": "cmdwin",
 				"help": "help",
-				"quickfix": "quickfix"
+				"quickfix": "quickfix",
+
+				"powerline.matchers.plugin.nerdtree.nerdtree": "plugin/nerdtree"
 			}
 		},
 		"wm": {

powerline/config_files/themes/vim/plugin/nerdtree.json

@@ -0,0 +1,17 @@
+{
+	"default_module": "powerline.segments.plugin.nerdtree",
+	"segments": {
+		"left": [
+			{
+				"name": "nerdtree"
+			},
+			{
+				"type": "string",
+				"highlight_group": ["background"],
+				"draw_soft_divider": false,
+				"draw_hard_divider": false,
+				"width": "auto"
+			}
+		]
+	}
+}

powerline/matchers/plugin/nerdtree.py

@@ -0,0 +1,9 @@
+# vim:fileencoding=utf-8:noet
+
+import os
+import re
+
+
+def nerdtree(matcher_info):
+	name = matcher_info['buffer'].name
+	return name and re.match(r'NERD_tree_\d+', os.path.basename(name))

powerline/segments/plugin/nerdtree.py

@@ -0,0 +1,17 @@
+# vim:fileencoding=utf-8:noet
+
+import vim
+
+from powerline.segments.vim import window_cached
+
+
+@window_cached
+def nerdtree(pl):
+	ntr = vim.eval('getbufvar("%", "NERDTreeRoot")')
+	if not ntr:
+		return
+	path_str = vim.eval('getbufvar("%", "NERDTreeRoot").path.str()')
+	return [{
+		'contents': path_str,
+		'highlight_group': ['nerdtree.path', 'file_name'],
+	}]