Add Hash#except ENV#except [Feature #15822]

hash.c

@@ -2822,6 +2822,33 @@ rb_hash_slice(int argc, VALUE *argv, VALUE hash)
     return result;
 }
 
+/*
+ *  call-seq:
+ *     hsh.except(*keys) -> a_hash
+ *
+ *  Returns a hash excluding the given keys and their values.
+ *
+ *     h = { a: 100, b: 200, c: 300 }
+ *     h.except(:a)          #=> {:b=>200, :c=>300}
+ *     h.except(:b, :c, :d)  #=> {:a=>100}
+ */
+
+static VALUE
+rb_hash_except(int argc, VALUE *argv, VALUE hash)
+{
+    int i;
+    VALUE key, result;
+
+    result = rb_obj_dup(hash);
+
+    for (i = 0; i < argc; i++) {
+        key = argv[i];
+        rb_hash_delete(result, key);
+    }
+
+    return result;
+}
+
 /*
  *  call-seq:
  *    hash.values_at(*keys) -> new_array
@@ -6877,6 +6904,29 @@ env_to_h(VALUE _)
     return hash;
 }
 
+/*
+ *  call-seq:
+ *     ENV.except(*keys) -> a_hash
+ *
+ *  Returns a hash except the given keys from ENV and their values.
+ *
+ *     ENV                       #=> {"LANG"="en_US.UTF-8", "TERM"=>"xterm-256color", "HOME"=>"/Users/rhc"}
+ *     ENV.except("TERM","HOME") #=> {"LANG"="en_US.UTF-8"}
+ */
+static VALUE
+env_except(int argc, VALUE *argv, VALUE _)
+{
+    int i;
+    VALUE key, hash = env_to_hash();
+
+    for (i = 0; i < argc; i++) {
+        key = argv[i];
+        rb_hash_delete(hash, key);
+    }
+
+    return hash;
+}
+
 /*
  * call-seq:
  *   ENV.reject { |name, value| block } -> hash of name/value pairs
@@ -7543,6 +7593,7 @@ Init_Hash(void)
     rb_define_method(rb_cHash, "reject", rb_hash_reject, 0);
     rb_define_method(rb_cHash, "reject!", rb_hash_reject_bang, 0);
     rb_define_method(rb_cHash, "slice", rb_hash_slice, -1);
+    rb_define_method(rb_cHash, "except", rb_hash_except, -1);
     rb_define_method(rb_cHash, "clear", rb_hash_clear, 0);
     rb_define_method(rb_cHash, "invert", rb_hash_invert, 0);
     rb_define_method(rb_cHash, "update", rb_hash_update, -1);
@@ -7678,6 +7729,7 @@ Init_Hash(void)
     rb_define_singleton_method(envtbl, "delete_if", env_delete_if, 0);
     rb_define_singleton_method(envtbl, "keep_if", env_keep_if, 0);
     rb_define_singleton_method(envtbl, "slice", env_slice, -1);
+    rb_define_singleton_method(envtbl, "except", env_except, -1);
     rb_define_singleton_method(envtbl, "clear", env_clear, 0);
     rb_define_singleton_method(envtbl, "reject", env_reject, 0);
     rb_define_singleton_method(envtbl, "reject!", env_reject_bang, 0);

test/ruby/test_env.rb

@@ -287,6 +287,17 @@ class TestEnv < Test::Unit::TestCase
     assert_equal({"foo"=>"bar", "baz"=>"qux"}, ENV.slice("foo", "baz"))
   end
 
+  def test_except
+    ENV.clear
+    ENV["foo"] = "bar"
+    ENV["baz"] = "qux"
+    ENV["bar"] = "rab"
+    assert_equal({"bar"=>"rab", "baz"=>"qux", "foo"=>"bar"}, ENV.except())
+    assert_equal({"bar"=>"rab", "baz"=>"qux", "foo"=>"bar"}, ENV.except(""))
+    assert_equal({"bar"=>"rab", "baz"=>"qux", "foo"=>"bar"}, ENV.except("unknown"))
+    assert_equal({"bar"=>"rab"}, ENV.except("foo", "baz"))
+  end
+
   def test_clear
     ENV.clear
     assert_equal(0, ENV.size)

test/ruby/test_hash.rb

@@ -1036,6 +1036,14 @@ class TestHash < Test::Unit::TestCase
     assert_equal({}, {}.slice)
   end
 
+  def test_except
+    h = @cls[1=>2,3=>4,5=>6]
+    assert_equal({5=>6}, h.except(1, 3))
+    assert_equal({1=>2,3=>4,5=>6}, h.except(7))
+    assert_equal({1=>2,3=>4,5=>6}, h.except)
+    assert_equal({}, {}.except)
+  end
+
   def test_filter
     assert_equal({3=>4,5=>6}, @cls[1=>2,3=>4,5=>6].filter {|k, v| k + v >= 7 })