add dir and file flags to NERDTreeIgnore regexes

This allows users to specify whether each regex in NERDTreeIgnore should
apply to only files or only dirs.

doc/NERD_tree.txt

@@ -780,6 +780,14 @@ For example if you put the following line in your vimrc: >
 <
 then all files ending in .vim or ~ will be ignored.
 
+There are 2 magic flags that can be appended to the end of each regular
+expression to specify that the regex should match only files or only dirs.
+These flags are "[[dir]]" and "[[file]]". Example: >
+    let NERDTreeIgnore=['.d$[[dir]]', '.o$[[file]]']
+<
+This will cause all dirs ending in ".d" to be ignored and all files ending in
+".o" to be ignored.
+
 Note: to tell the NERD tree not to ignore any files you must use the following
 line: >
     let NERDTreeIgnore=[]
@@ -1129,6 +1137,7 @@ The latest dev versions are on github
 Next
     - add 'scope' argument to the key map API
     - add NERDTreeCustomIgnoreFilter hook - needs doc
+    - add magic [[dir]] and [[file]] flags to NERDTreeIgnore
 
 4.2.0
     - Add NERDTreeDirArrows option to make the UI use pretty arrow chars

plugin/NERD_tree.vim

@@ -2291,19 +2291,17 @@ endfunction
 "FUNCTION: Path.ignore() {{{3
 "returns true if this path should be ignored
 function! s:Path.ignore()
-    let lastPathComponent = self.getLastPathComponent(0)
-
     "filter out the user specified paths to ignore
     if b:NERDTreeIgnoreEnabled
         for i in g:NERDTreeIgnore
-            if lastPathComponent =~# i
+            if self._ignorePatternMatches(i)
                 return 1
             endif
         endfor
     endif
 
     "dont show hidden files unless instructed to
-    if b:NERDTreeShowHidden ==# 0 && lastPathComponent =~# '^\.'
+    if b:NERDTreeShowHidden ==# 0 && self.getLastPathComponent(0) =~# '^\.'
         return 1
     endif
 
@@ -2318,6 +2316,24 @@ function! s:Path.ignore()
     return 0
 endfunction
 
+"FUNCTION: Path._ignorePatternMatches(pattern) {{{3
+"returns true if this path matches the given ignore pattern
+function! s:Path._ignorePatternMatches(pattern)
+    let pat = a:pattern
+    if strpart(pat,len(pat)-7) == '[[dir]]'
+        if !self.isDirectory
+            return 0
+        endif
+        let pat = strpart(pat,0, len(pat)-7)
+    elseif strpart(pat,len(pat)-8) == '[[file]]'
+        if self.isDirectory
+            return 0
+        endif
+        let pat = strpart(pat,0, len(pat)-8)
+    endif
+
+    return self.getLastPathComponent(0) =~# pat
+endfunction
 "FUNCTION: Path.isUnder(path) {{{3
 "return 1 if this path is somewhere under the given path in the filesystem.
 "