Add a NERDTreeMinimalMenu feature (#938)

* Extract the menu action prompts to a function

* Add a NERDTreeMinimalMenu configuration option

If this option is set, Vim’s command line displays
a single-line version of the menu:

Which action? (a*/m/d/r/o/q/c/l):

Pressing ‘a’ will call the ‘add child node’ menu
item as that is its shortcut.

The * denotes the position of the currently
selected menu item which can be changed with
NERDTreeMenuDown and Up in the usual way.

The user may wish to set these to <left>, <right>
or h, l if they prefer.

* Minimise the text once a menu item is chosen

If NERDTreeMinimalMenu is set, then echo a single
line prompt after the menu item is chosen. This
reduces noise for users who are already familiar
with how the menu works and prevents Vim scrolling
down to accommodate the menu text.

If the directory is non-empty we display
‘Delete directory?’ instead of ‘Delete?’ and the
user must still type ‘yes’ to confirm, rather than
just pressing ‘y’.

* Document the new NERDTreeMinimalMenu feature

* Tweak the format for the minimal menu prompt

As per @PhilRunninger’s suggestions:

- The menu now shows the ‘j/k/enter’ help text
- The first word of the selected item is shown*
- Use commas between menu items so that it’s
  visually distinct from the ‘j/k/enter’ text

* I tried displaying the full menuItem text, but
this can be quite long, e.g.

> (o)pen the current node with system editor

This causes the menu to jump around a lot. We
could add another minimal versions of these, but
I think the first word seems ok for now.

doc/NERDTree.txt

@@ -719,6 +719,9 @@ the NERD tree. These settings should be set in your vimrc, using `:let`.
 |NERDTreeMinimalUI|           Disables display of the 'Bookmarks' label and
                             'Press ? for help' text.
 
+|NERDTreeMinimalMenu|         Use a compact menu that fits on a single line
+                            for adding, copying, deleting, etc
+
 |NERDTreeCascadeSingleChildDir|
                             Collapses on the same line directories that have
                             only one child directory.
@@ -1116,6 +1119,26 @@ of the following lines for this setting: >
     let NERDTreeMinimalUI=1
 <
 
+------------------------------------------------------------------------------
+                                                             *NERDTreeMinimalMenu*
+Values: 0 or 1
+Default: 0
+
+This setting makes NERD tree use a smaller, more compact menu for adding,
+copying, deleting nodes. This menu fits on a single line so Vim doesn't need to
+scroll down to present it. This setting is recommended for users already
+familiar with the menu items. It will look similar to this:
+
+  Menu: [ (a)dd ,m,d,r,o,q,c,l] (Use j/k/enter or shortcut):
+
+An action can be selected with its shortcut key or with the NERDTreeMenuUp and
+NERDTreeMenuDown keys, then pressing enter.
+
+Use one of the following lines for this setting: >
+    let NERDTreeMinimalMenu=0
+    let NERDTreeMinimalMenu=1
+
+
 ------------------------------------------------------------------------------
                                                  *NERDTreeCascadeSingleChildDir*
 Values: 0 or 1

lib/nerdtree/menu_controller.vim

@@ -15,6 +15,11 @@ function! s:MenuController.New(menuItems)
     return newMenuController
 endfunction
 
+" FUNCTION: s:MenuController.isMinimal() {{{1
+function! s:MenuController.isMinimal()
+    return g:NERDTreeMinimalMenu
+endfunction
+
 " FUNCTION: MenuController.showMenu() {{{1
 " Enter the main loop of the NERDTree menu, prompting the user to select
 " a menu item.
@@ -49,8 +54,18 @@ endfunction
 
 "FUNCTION: MenuController._echoPrompt() {{{1
 function! s:MenuController._echoPrompt()
-    echo "NERDTree Menu. Use " . g:NERDTreeMenuDown . "/" . g:NERDTreeMenuUp . "/enter and the shortcuts indicated"
+    let navHelp = "Use " . g:NERDTreeMenuDown . "/" . g:NERDTreeMenuUp . "/enter"
-    echo "=========================================================="
+
+    if self.isMinimal()
+        let selection = self.menuItems[self.selection].text
+
+        let shortcuts = map(copy(self.menuItems), "v:val['shortcut']")
+        let shortcuts[self.selection] = " " . split(selection)[0] . " "
+
+        echo "Menu: [" . join(shortcuts, ",") . "] (" . navHelp . " or shortcut): "
+    else
+        echo "NERDTree Menu. " . navHelp . " . or the shortcuts indicated"
+        echo "========================================================="
 
         for i in range(0, len(self.menuItems)-1)
             if self.selection == i
@@ -59,6 +74,7 @@ function! s:MenuController._echoPrompt()
                 echo "  " . self.menuItems[i].text
             endif
         endfor
+    endif
 endfunction
 
 "FUNCTION: MenuController._current(key) {{{1
@@ -129,7 +145,11 @@ endfunction
 "FUNCTION: MenuController._setCmdheight() {{{1
 "sets &cmdheight to whatever is needed to display the menu
 function! s:MenuController._setCmdheight()
+    if self.isMinimal()
+        let &cmdheight = 1
+    else
         let &cmdheight = len(self.menuItems) + 3
+    endif
 endfunction
 
 "FUNCTION: MenuController._saveOptions() {{{1

nerdtree_plugin/fs_menu.vim

@@ -44,6 +44,47 @@ else
     call NERDTreeAddMenuItem({'text': '(l)ist the current node', 'shortcut': 'l', 'callback': 'NERDTreeListNodeWin32'})
 endif
 
+"FUNCTION: s:inputPrompt(action){{{1
+"returns the string that should be prompted to the user for the given action
+"
+"Args:
+"action: the action that is being performed, e.g. 'delete'
+function! s:inputPrompt(action)
+    if a:action == "add"
+        let title = "Add a childnode"
+        let info = "Enter the dir/file name to be created. Dirs end with a '/'"
+        let minimal = "Add node:"
+
+    elseif a:action == "copy"
+        let title = "Copy the current node"
+        let info = "Enter the new path to copy the node to:"
+        let minimal = "Copy to:"
+
+    elseif a:action == "delete"
+        let title = "Delete the current node"
+        let info = "Are you sure you wish to delete the node:"
+        let minimal = "Delete?"
+
+    elseif a:action == "deleteNonEmpty"
+        let title = "Delete the current node"
+        let info =  "STOP! Directory is not empty! To delete, type 'yes'"
+        let minimal = "Delete directory?"
+
+    elseif a:action == "move"
+        let title = "Rename the current node"
+        let info = "Enter the new path for the node:"
+        let minimal = "Move to:"
+    endif
+
+    if g:NERDTreeMenuController.isMinimal()
+        redraw! " Clear the menu
+        return minimal . " "
+    else
+        let divider = "=========================================================="
+        return title . "\n" . divider . "\n" . info . "\n"
+    end
+endfunction
+
 "FUNCTION: s:promptToDelBuffer(bufnum, msg){{{1
 "prints out the given msg and, if the user responds by pushing 'y' then the
 "buffer with the given bufnum is deleted
@@ -114,14 +155,12 @@ function! s:renameBuffer(bufNum, newNodeName, isDirectory)
         " This happens when answering Cancel if confirmation is needed. Do nothing.
     endtry
 endfunction
+
 "FUNCTION: NERDTreeAddNode(){{{1
 function! NERDTreeAddNode()
     let curDirNode = g:NERDTreeDirNode.GetSelected()
-
+    let prompt = s:inputPrompt("add")
-    let newNodeName = input("Add a childnode\n".
+    let newNodeName = input(prompt, curDirNode.path.str() . g:NERDTreePath.Slash(), "file")
-                          \ "==========================================================\n".
-                          \ "Enter the dir/file name to be created. Dirs end with a '/'\n" .
-                          \ "", curDirNode.path.str() . g:NERDTreePath.Slash(), "file")
 
     if newNodeName ==# ''
         call nerdtree#echo("Node Creation Aborted.")
@@ -144,6 +183,8 @@ function! NERDTreeAddNode()
             call NERDTreeRender()
             call newTreeNode.putCursorHere(1, 0)
         endif
+
+        redraw!
     catch /^NERDTree/
         call nerdtree#echoWarning("Node Not Created.")
     endtry
@@ -152,10 +193,8 @@ endfunction
 "FUNCTION: NERDTreeMoveNode(){{{1
 function! NERDTreeMoveNode()
     let curNode = g:NERDTreeFileNode.GetSelected()
-    let newNodePath = input("Rename the current node\n" .
+    let prompt = s:inputPrompt("move")
-                          \ "==========================================================\n" .
+    let newNodePath = input(prompt, curNode.path.str(), "file")
-                          \ "Enter the new path for the node:                          \n" .
-                          \ "", curNode.path.str(), "file")
 
     if newNodePath ==# ''
         call nerdtree#echo("Node Renaming Aborted.")
@@ -194,7 +233,7 @@ function! NERDTreeMoveNode()
 
         call curNode.putCursorHere(1, 0)
 
-        redraw
+        redraw!
     catch /^NERDTree/
         call nerdtree#echoWarning("Node Not Renamed.")
     endtry
@@ -209,21 +248,16 @@ function! NERDTreeDeleteNode()
 
     if currentNode.path.isDirectory && ((currentNode.isOpen && currentNode.getChildCount() > 0) ||
                                       \ (len(currentNode._glob('*', 1)) > 0))
-        let choice =input("Delete the current node\n" .
+        let prompt = s:inputPrompt("deleteNonEmpty") . currentNode.path.str() . ": "
-                         \ "==========================================================\n" .
+        let choice = input(prompt)
-                         \ "STOP! Directory is not empty! To delete, type 'yes'\n" .
-                         \ "" . currentNode.path.str() . ": ")
         let confirmed = choice ==# 'yes'
     else
-        echo "Delete the current node\n" .
+        let prompt = s:inputPrompt("delete") . currentNode.path.str() . " (yN): "
-           \ "==========================================================\n".
+        echo prompt
-           \ "Are you sure you wish to delete the node:\n" .
-           \ "" . currentNode.path.str() . " (yN):"
         let choice = nr2char(getchar())
         let confirmed = choice ==# 'y'
     endif
 
-
     if confirmed
         try
             call currentNode.delete()
@@ -237,7 +271,7 @@ function! NERDTreeDeleteNode()
                 call s:promptToDelBuffer(bufnum, prompt)
             endif
 
-            redraw
+            redraw!
         catch /^NERDTree/
             call nerdtree#echoWarning("Could not remove node")
         endtry
@@ -292,10 +326,8 @@ function! NERDTreeCopyNode()
     let l:shellslash = &shellslash
     let &shellslash = 0
     let currentNode = g:NERDTreeFileNode.GetSelected()
-    let newNodePath = input("Copy the current node\n" .
+    let prompt = s:inputPrompt("copy")
-                          \ "==========================================================\n" .
+    let newNodePath = input(prompt, currentNode.path.str(), "file")
-                          \ "Enter the new path to copy the node to:                   \n" .
-                          \ "", currentNode.path.str(), "file")
 
     if newNodePath != ""
         "strip trailing slash
@@ -329,7 +361,7 @@ function! NERDTreeCopyNode()
         call nerdtree#echo("Copy aborted.")
     endif
     let &shellslash = l:shellslash
-    redraw
+    redraw!
 endfunction
 
 " FUNCTION: NERDTreeQuickLook() {{{1

plugin/NERD_tree.vim

@@ -51,6 +51,7 @@ call s:initVariable("g:NERDTreeSortHiddenFirst", 1)
 call s:initVariable("g:NERDTreeChDirMode", 0)
 call s:initVariable("g:NERDTreeCreatePrefix", "silent")
 call s:initVariable("g:NERDTreeMinimalUI", 0)
+call s:initVariable("g:NERDTreeMinimalMenu", 0)
 if !exists("g:NERDTreeIgnore")
     let g:NERDTreeIgnore = ['\~$']
 endif