Ruby: Add method KernAux.sprintf

pkgs/ruby/lib/kernaux.rb

@@ -20,6 +20,16 @@ module KernAux
     assert_do file, Integer(line), msg
   end
 
+  def self.sprintf(*args)
+    args.map do |arg|
+      if arg.is_a? Array
+        sprintf1(*arg)
+      else
+        arg
+      end
+    end.join.freeze
+  end
+
   def self.sprintf1(format, arg = nil)
     if arg.nil?
       snprintf1(SPRINTF1_BUFFER_SIZE, format).first

pkgs/ruby/spec/lib/kernaux/sprintf_spec.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe KernAux, '.sprintf' do
+  subject(:sprintf) { described_class.sprintf 'Hello, ', ['%s', 'World'], '!' }
+
+  it { is_expected.to be_instance_of String }
+  it { is_expected.to be_frozen }
+  it { is_expected.to eq 'Hello, World!' }
+end