diff --git a/autoload/vital/__vital__/System/Filepath.vim b/autoload/vital/__vital__/System/Filepath.vim
index dc2b5df17..e3fe88151 100644
--- a/autoload/vital/__vital__/System/Filepath.vim
+++ b/autoload/vital/__vital__/System/Filepath.vim
@@ -14,6 +14,27 @@ let s:is_mac = !s:is_windows && !s:is_cygwin
       \   (!isdirectory('/proc') && executable('sw_vers')))
 let s:is_case_tolerant = filereadable(expand('<sfile>:r') . '.VIM')
 
+if s:is_windows
+  function! s:to_slash(path) abort
+    return tr(a:path, '\', '/')
+  endfunction
+else
+  function! s:to_slash(path) abort
+    return a:path
+  endfunction
+endif
+
+if s:is_windows
+  function! s:from_slash(path) abort
+    return tr(a:path, '/', '\')
+  endfunction
+else
+  function! s:from_slash(path) abort
+    return a:path
+  endfunction
+endif
+
+
 " Get the directory separator.
 function! s:separator() abort
   return fnamemodify('.', ':p')[-1 :]
diff --git a/doc/vital/System/Filepath.txt b/doc/vital/System/Filepath.txt
index b69eb2ea1..b72080ffa 100644
--- a/doc/vital/System/Filepath.txt
+++ b/doc/vital/System/Filepath.txt
@@ -21,6 +21,29 @@ INTERFACE				*Vital.System.Filepath-interface*
 ------------------------------------------------------------------------------
 FUNCTIONS				*Vital.System.Filepath-functions*
 
+to_slash({path})			*Vital.System.Filepath.to_slash()*
+	Use when you quote path string for scripting languages, without
+	worrying about the runtime operating system is if windows or not.
+
+	e.g.
+>
+	let code = printf(
+	  \ '(neoclojure-init "%s")',
+	  \ shellescape(s:F.to_slash(path)))
+	..
+	let path = s:F.from_slash(
+	  \ s:get_path_like_string_from_something())
+<
+
+	This function intentionally ignores 'shellslash' option, so that you
+	can simply use this function for path string not only from Vim but
+	also from others, such as environment vars, problem output, or really
+	anything.
+	See also: |Vital.System.Filepath.from_slash()|
+
+from_slash({path})			*Vital.System.Filepath.from_slash()*
+	This is opposite to |Vital.System.Filepath.to_slash()|. See its doc.
+
 separator()			*Vital.System.Filepath.separator()*
 	Return OS related directory separator as string.
 	This returns "/" on non-Windows, or Windows and |'shellslash'| is on.
diff --git a/test/System/Filepath.vimspec b/test/System/Filepath.vimspec
index c477eb683..e4462b0d1 100644
--- a/test/System/Filepath.vimspec
+++ b/test/System/Filepath.vimspec
@@ -8,6 +8,27 @@ Describe System.Filepath
     let is_case_sensitive_file_system = !(isdirectory(tolower(g:root)) && isdirectory(toupper(g:root)))
   End
 
+  Describe .to_slash()
+    It converts / to \ only when it's necessary
+      Assert Equals('a/b', FP.to_slash('a/b'))
+      if has('win32') || has('win64')
+        Assert Equals('a/b', FP.to_slash('a\b'))
+      else
+        Assert Equals('a\b', FP.to_slash('a\b'))
+      endif
+    End
+  End
+
+  Describe .from_slash()
+    It converts \ to / only when it's necessary
+      if has('win32') || has('win64')
+        Assert Equals('a\b', FP.from_slash('a/b'))
+      else
+        Assert Equals('a/b', FP.from_slash('a/b'))
+      endif
+    End
+  End
+
   Describe .is_absolute()
     if !s:is_windows
       It returns TRUE if {path} is an absolute path