Add `Hash#except` [Ruby 3.0]

mrbgems/mruby-hash-ext/src/hash-ext.c

@@ -69,6 +69,31 @@ hash_slice(mrb_state *mrb, mrb_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 mrb_value
+hash_except(mrb_state *mrb, mrb_value hash)
+{
+  const mrb_value *argv;
+  mrb_value result;
+  mrb_int argc, i;
+
+  mrb_get_args(mrb, "*", &argv, &argc);
+  result = mrb_hash_dup(mrb, hash);
+  for (i = 0; i < argc; i++) {
+    mrb_hash_delete_key(mrb, result, argv[i]);
+  }
+  return result;
+}
+
 void
 mrb_mruby_hash_ext_gem_init(mrb_state *mrb)
 {
@@ -77,6 +102,7 @@ mrb_mruby_hash_ext_gem_init(mrb_state *mrb)
   h = mrb->hash_class;
   mrb_define_method(mrb, h, "values_at", hash_values_at, MRB_ARGS_ANY());
   mrb_define_method(mrb, h, "slice",     hash_slice, MRB_ARGS_ANY());
+  mrb_define_method(mrb, h, "except",    hash_except, MRB_ARGS_ANY());
 }
 
 void

mrbgems/mruby-hash-ext/test/hash.rb

@@ -288,3 +288,10 @@ assert("Hash#slice") do
   assert_equal({:a=>100}, h.slice(:a))
   assert_equal({:b=>200, :c=>300}, h.slice(:b, :c, :d))
 end
+
+assert("Hash#except") do
+  h = { a: 100, b: 200, c: 300 }
+  assert_equal({:b=>200, :c=>300}, h.except(:a))
+  assert_equal({:a=>100}, h.except(:b, :c, :d))
+  assert_equal(h, h.except)
+end