Add File.exists?

lib/file.ex

@@ -28,6 +28,21 @@ defmodule File do
     FL.is_dir(directory)
   end
 
+  @doc """
+  Returns if `file` exists
+
+  ## Examples
+
+    File.exists?("/tmp")
+    #=> true
+
+    File.exists?("missing.txt")
+    #=> false
+  """
+  def exists?(filename) do
+    is_tuple(FL.last_modified(filename))
+  end
+
   @doc """
   Returns the last component of the `filename` or the file
   name itself if it does not contain any directory separators.

test/elixir/file_test.exs

@@ -32,6 +32,14 @@ defmodule FileTest do
     refute File.regular?("#{__FILE__}.unknown")
   end
 
+  test :exists do
+    assert File.exists?(__FILE__)
+    assert File.exists?(File.expand_path("../fixtures/foo.txt", __FILE__))
+
+    refute File.exists?("fixtures/missing.txt")
+    refute File.exists?("_missing.txt")
+  end
+
   test :basename_with_binary do
     assert File.basename("foo") == "foo"
     assert File.basename("/foo/bar") == "bar"