Implemented Dir.children (crystal-lang#4808)

spec/std/dir_spec.cr

@@ -256,9 +256,15 @@ describe "Dir" do
 
   it "lists entries" do
     filenames = Dir.entries(__DIR__)
+    filenames.includes?(".").should be_true
+    filenames.includes?("..").should be_true
     filenames.includes?("dir_spec.cr").should be_true
   end
 
+  it "lists children" do
+    Dir.children(__DIR__).should eq(Dir.entries(__DIR__) - %w(. ..))
+  end
+
   it "does to_s" do
     Dir.new(__DIR__).to_s.should eq("#<Dir:#{__DIR__}>")
   end

src/dir.cr

@@ -154,6 +154,17 @@ class Dir
     entries
   end
 
+  # Returns an array containing all of the filenames except for `.` and `..`
+  # in the given directory.
+  def self.children(dirname) : Array(String)
+    excluded = {".", ".."}
+    entries = [] of String
+    foreach(dirname) do |filename|
+      entries << filename unless excluded.includes?(filename)
+    end
+    entries
+  end
+
   # Returns `true` if the given path exists and is a directory
   def self.exists?(path) : Bool
     if LibC.stat(path.check_no_null_byte, out stat) != 0