diff --git a/bin/scottkit b/bin/scottkit
index 789cd33..5da3529 100755
--- a/bin/scottkit
+++ b/bin/scottkit
@@ -17,7 +17,6 @@ $VERBOSE = true
 require 'optparse'
 require 'stringio'
 require 'scottkit/game'
-require 'scottkit/withio'
 
 
 def play(game)
@@ -110,19 +109,17 @@ exitval = 0
 game = ScottKit::Game.new(options)
 case mode
 when :play_from_source
-  f = StringIO.new
-  withIO(nil, f) do
-    if !game.compile_to_stdout(ARGV[0])
-      $stderr.puts "#$0: compilation failed: not playing"
-      exitval = 1
-    end
+  compiled_game = StringIO.new
+  if !game.compile(compiled_game, ARGV[0])
+    $stderr.puts "#$0: compilation failed: not playing"
+    exitval = 1
   end
   if exitval == 0
-    game.load(f.string)
+    game.load(compiled_game.string)
     play(game)
   end
 when :compile
-  if !game.compile_to_stdout(ARGV[0])
+  if !game.compile($stdout, ARGV[0])
     $stderr.puts "#$0: compilation failed"
     exitval = 1
   end
diff --git a/lib/scottkit/compile.rb b/lib/scottkit/compile.rb
index a66c0ac..4fd2d4f 100644
--- a/lib/scottkit/compile.rb
+++ b/lib/scottkit/compile.rb
@@ -5,8 +5,6 @@
 module ScottKit
   class Game
     class Compiler
-      private
-
       # Creates a new compiler for the specified game, set up ready to
       # compile the game in the specified file.
       #
@@ -25,17 +23,17 @@ def initialize(game, filename, fh = nil)
       end
 
       # Compiles the specified game-source file, writing the resulting
-      # object file to stdout, whence it should be redirected into a
+      # object file to an IO stream, whence it should be redirected into a
       # file so that it can be played.  Yes, this API is sucky: it
       # would be better if we had a simple compile method that builds
       # the game in memory in a form that can by played, and which can
       # then also be saved as an object file by some other method --
       # but that would have been more work for little gain.
       #
-      def compile_to_stdout
+      def compile_to(output)
         begin
           tree = parse
-          generate_code(tree)
+          generate_code(tree, output)
           true
         rescue
           return false if String($!) == "syntax error"
@@ -81,6 +79,8 @@ def parse
                   items, actions, verbgroups, noungroups)
       end
 
+      private
+
       def parse_room
         match :room
         name = match :symbol
@@ -139,7 +139,7 @@ def parse_occur
         end
 
         conds, instructions, comment = parse_actionbody
-        CAction.new(nil, chance, conds, instructions, comment)        
+        CAction.new(nil, chance, conds, instructions, comment)
       end
 
       def parse_actionbody
@@ -207,7 +207,7 @@ def match(token, estr = nil); @lexer.match token, estr; end
       def error(str); @lexer.error str; end
 
 
-      def generate_code(tree)
+      def generate_code(tree, output)
         lintOptions = @game.options[:lint] || ''
         @had_errors = false
         rooms = tree.rooms
@@ -267,7 +267,7 @@ def generate_code(tree)
           dead_ends = []
           rooms.each.with_index do |room, index|
             next if index == 0
-            next if 
+            next if
             if room.exits.length == 0
               no_exits.push room.name
             elsif room.exits.length == 1
@@ -439,76 +439,76 @@ def generate_code(tree)
         return if @had_errors
 
         # Write header
-        puts tree.unknown1 || 0
-        puts items.size-1
-        puts actions.size-1
-        puts verbs.size-1
-        puts rooms.size-1
-        puts tree.maxload || -1
-        puts startindex
-        puts items.select { |x| x.desc[0] == "*" }.count
-        puts tree.wordlen
-        puts tree.lighttime || -1
-        puts messages.size-1
-        puts treasuryindex
-        puts # Blank line
+        output.puts tree.unknown1 || 0
+        output.puts items.size-1
+        output.puts actions.size-1
+        output.puts verbs.size-1
+        output.puts rooms.size-1
+        output.puts tree.maxload || -1
+        output.puts startindex
+        output.puts items.select { |x| x.desc[0] == "*" }.count
+        output.puts tree.wordlen
+        output.puts tree.lighttime || -1
+        output.puts messages.size-1
+        output.puts treasuryindex
+        output.puts # Blank line
 
         # Actions
         actions.each do |action|
-          print 150*action.verb + action.noun, " "
+          output.print 150*action.verb + action.noun, " "
 
-          print action.conds.map { |x| String(x[0] + 20 * x[1]) + " " }.join
-          print action.gathered_args.map { |x| String(20*x) + " " }.join
+          output.print action.conds.map { |x| String(x[0] + 20 * x[1]) + " " }.join
+          output.print action.gathered_args.map { |x| String(20*x) + " " }.join
           nconds = action.conds.size + action.gathered_args.size
           raise "condition has #{nconds} conditions" if nconds > 5
-          (5-nconds).times { print "0 " }
+          (5-nconds).times { output.print "0 " }
 
           ins = action.instructions.map { |x| x[0] }
           (4-ins.count).times { ins << 0 }
-          puts "#{150*ins[0] + ins[1]} #{150*ins[2] + ins[3]}\n"
+          output.puts "#{150*ins[0] + ins[1]} #{150*ins[2] + ins[3]}\n"
         end
-        puts # Blank line
+        output.puts # Blank line
 
         # Vocab
         verbs.each.with_index do |verb, i|
-          puts "\"#{verb}\" \"#{nouns[i]}\""
+          output.puts "\"#{verb}\" \"#{nouns[i]}\""
         end
-        puts # Blank line
+        output.puts # Blank line
 
         # Rooms
         rooms.each do |room|
           0.upto(5).each do |i|
             exit = room.exits[@game.dirname(i)]
-            print(exit ? exit : 0, " ")
+            output.print(exit ? exit : 0, " ")
           end
-          print "\"#{room.desc}\"\n"
+          output.print "\"#{room.desc}\"\n"
         end
-        puts # Blank line
+        output.puts # Blank line
 
         # Messages
         messages.each do |message|
-          puts "\"#{message}\"\n"
+          output.puts "\"#{message}\"\n"
         end
-        puts # Blank line
+        output.puts # Blank line
 
         # Items
         items.each do |item|
           desc = item.desc
           desc += "/" + item.called.upcase[0, @wordlen] + "/" if item.called
-          puts "\"#{desc}\" #{item.where}"
+          output.puts "\"#{desc}\" #{item.where}"
         end
-        puts # Blank line
+        output.puts # Blank line
 
         # Action comments
         actions.each do |action|
-          puts "\"#{action.comment || ""}\"\n"
+          output.puts "\"#{action.comment || ""}\"\n"
         end
-        puts # Blank line
+        output.puts # Blank line
 
         # Trailer
-        puts tree.version || 0
-        puts tree.ident || 0
-        puts tree.unknown2 || 0
+        output.puts tree.version || 0
+        output.puts tree.ident || 0
+        output.puts tree.unknown2 || 0
       end
 
       def room_by_name(loc, roommap)
@@ -560,10 +560,6 @@ def gwarning(str)
         0
       end
 
-      public :compile_to_stdout # Must be visible to Game.compile()
-      public :parse # Used by test_compile.rb
-
-
       CGame = Struct.new(:ident, :version, :unknown1, :unknown2,
                          :start, :treasury, :maxload, :wordlen,
                          :lighttime, :lightsource, :rooms, :items,
diff --git a/lib/scottkit/game.rb b/lib/scottkit/game.rb
old mode 100755
new mode 100644
index 7130fdf..c5a0db1
--- a/lib/scottkit/game.rb
+++ b/lib/scottkit/game.rb
@@ -20,11 +20,12 @@ class Game
     attr_reader :flags, :counters, :saved_rooms, :noun #:nodoc:
     attr_accessor :loc, :counter, :saved_room, :lampleft #:nodoc:
 
-    private
+    attr_reader :input, :output
 
     # Creates a new game, with no room, items or actions -- load must
-    # be called to make the game ready for playing, or
-    # compile_to_stdout can be called to generate a new game-file.
+    # be called to make the game ready for playing, or compile can be
+    # called to generate a new game-file.
+    #
     # The options hash affects various aspects of how the game will be
     # loaded, played and compiled.  The following symbols are
     # recognised as keys in the options hash:
@@ -44,10 +45,18 @@ class Game
     #                       file to restore before starting to play.
     #
     # [+read_file+]         If specified, the name of a file of game
-    #                       commands to be run after restoring s saved
+    #                       commands to be run after restoring a saved
     #                       game (if any) and before starting to read
     #                       commands from the user.
     #
+    # [+output+]            If specified, a writable IO stream for
+    #                       capturing the game's output.  Defaults to
+    #                       <tt>$stdout</tt> if nothing is provided.
+    #
+    # [+input+]             If specified, a readable IO stream for
+    #                       capturing the game's input.  Defaults to
+    #                       <tt>$stdin</tt> if nothing is provided.
+    #
     # [+echo_input+]        If true, then game commands are echoed
     #                       before being executed.  This is useful
     #                       primarily if input is being redirected
@@ -106,8 +115,25 @@ def initialize(options)
       @options = options
       @rooms, @items, @actions, @nouns, @verbs, @messages =
         [], [], [], [], [], []
+      @input  = options[:input]  || $stdin
+      @output = options[:output] || $stdout
+    end
+
+    def puts *args
+      output.puts(*args)
+    end
+
+    def print *args
+      output.print(*args)
     end
 
+    # Print debugging output
+    def dputs(level, *args) #:nodoc:
+      super.puts args.map { |x| "# #{x}" } if @options[level]
+    end
+
+    private
+
     # Virtual accessor
     def dark_flag #:nodoc:
       @flags[FLAG_DARK]
@@ -261,10 +287,6 @@ def restore(name)
       @items.each { |item| item.loc = f.gets.to_i }
     end
 
-    def dputs(level, *args) #:nodoc:
-      puts args.map { |x| "# #{x}" } if @options[level]
-    end
-
     # Compiles the specified game-source file, writing the resulting
     # object file to stdout, whence it should be redirected into a
     # file so that it can be played.  Yes, this API is sucky: it would
@@ -283,14 +305,12 @@ def dputs(level, *args) #:nodoc:
     # function is that its behaviour is influenced by the game's
     # options.)
     #
-    def compile_to_stdout(filename, fh = nil)
-      compiler = ScottKit::Game::Compiler.new(self, filename, fh)
-      compiler.compile_to_stdout
+    def compile(out, filename, fh = nil)
+      ScottKit::Game::Compiler.new(self, filename, fh).compile_to(out)
     end
 
-    public :load, :compile_to_stdout # Must be visible to driver program
+    public :load, :compile # Must be visible to driver program
     public :roomname, :itemname # Needed by Condition.render()
-    public :dputs # Needed for contained classes' debugging output
     public :dirname # Needed by compiler
     public :dark_flag= # Invoked from Instruction.execute()
 
diff --git a/lib/scottkit/play.rb b/lib/scottkit/play.rb
index c3d1421..5cf3abe 100644
--- a/lib/scottkit/play.rb
+++ b/lib/scottkit/play.rb
@@ -93,14 +93,15 @@ def process_lighting
       end
     end
 
-    # Get a line from @fh if defined, otherwise $stdin
+    # Get a line from @fh if defined, otherwise input
     def gets
       line = nil
       if (@fh)
         line = @fh.gets
+        # Clear the read_file handle when all the input is consumed.
         @fh = nil if !line
       end
-      line = $stdin.gets if !line
+      line = input.gets if !line
       return nil if !line
       puts line if @fh || options[:echo_input]
       line
@@ -411,15 +412,15 @@ def execute(args)
         if (@op == 0)
           return false # shouldn't happen
         elsif (@op <= 51)
-          puts @game.messages[@op].gsub('`', '"')
+          @game.puts @game.messages[@op].gsub('`', '"')
           return false
         elsif (@op >= 102)
-          puts @game.messages[@op-50].gsub('`', '"')
+          @game.puts @game.messages[@op-50].gsub('`', '"')
           return false
         else case @op
         when 52 then
           if @game.ncarried == @game.maxload
-            puts "I've too much to carry!"
+            @game.puts "I've too much to carry!"
           else
             @game.items[args.shift].loc = ROOM_CARRIED
           end
@@ -432,7 +433,7 @@ def execute(args)
         when 59 then @game.items[args.shift].loc = ROOM_NOWHERE
         when 60 then @game.flags[args.shift] = false
         when 61 then
-          puts "I am dead."; @game.flags[15] = false;
+          @game.puts "I am dead."; @game.flags[15] = false;
           @game.loc = @game.rooms.size-1; @game.need_to_look
         when 62 then i = args.shift; @game.items[i].loc = args.shift
         when 63 then @game.finish(0)
@@ -457,7 +458,7 @@ def execute(args)
           @game.items[i1].loc = @game.items[i2].loc
         when 76 then @game.need_to_look
         when 77 then @game.counter -= 1
-        when 78 then print @game.counter, " "
+        when 78 then @game.print @game.counter, " "
         when 79 then @game.counter = args.shift
         when 80 then @game.loc, @game.saved_room = @game.saved_room, @game.loc
         when 81 then which = args.shift
@@ -465,9 +466,9 @@ def execute(args)
             @game.counters[which], @game.counter
         when 82 then @game.counter += args.shift
         when 83 then @game.counter -= args.shift
-        when 84 then print @game.noun
-        when 85 then puts @game.noun
-        when 86 then puts
+        when 84 then @game.print @game.noun
+        when 85 then @game.puts @game.noun
+        when 86 then @game.puts
         when 87 then which = args.shift
           @game.loc, @game.saved_rooms[which] =
             @game.saved_rooms[which], @game.loc
diff --git a/lib/scottkit/withio.rb b/lib/scottkit/withio.rb
deleted file mode 100644
index e35e388..0000000
--- a/lib/scottkit/withio.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-# Provides a utility method withIO() used by several test-cases.  Runs
-# the specified block with stdin and stdout replumbed to the provided
-# file-handles; the old values of stdin and stdout are passed to the
-# block, in case they should be needed.
-
-def withIO(newin, newout)
-  old_STDIN = $stdin
-  old_STDOUT = $stdout
-  $stdin = newin
-  $stdout = newout
-  yield old_STDIN, old_STDOUT
-ensure
-  $stdin = old_STDIN
-  $stdout = old_STDOUT
-end
diff --git a/scottkit.gemspec b/scottkit.gemspec
index 803dd3f..eb23821 100644
--- a/scottkit.gemspec
+++ b/scottkit.gemspec
@@ -99,7 +99,6 @@ Gem::Specification.new do |s|
     "lib/scottkit/decompile.rb",
     "lib/scottkit/game.rb",
     "lib/scottkit/play.rb",
-    "lib/scottkit/withio.rb",
     "scottkit.gemspec",
     "test/test_canonicalise.rb",
     "test/test_compile.rb",
@@ -107,7 +106,6 @@ Gem::Specification.new do |s|
     "test/test_play.rb",
     "test/test_playadams.rb",
     "test/test_save.rb",
-    "test/withio_test.rb"
   ]
   s.homepage = "http://github.com/MikeTaylor/scottkit".freeze
   s.licenses = ["GPL-2.0".freeze]
diff --git a/test/test_canonicalise.rb b/test/test_canonicalise.rb
index 79d5a26..c6c5438 100644
--- a/test/test_canonicalise.rb
+++ b/test/test_canonicalise.rb
@@ -1,7 +1,6 @@
 require 'test/unit'
 require 'scottkit/game'
 require 'stringio'
-require 'scottkit/withio'
 
 # The idea here is that we can start with a source file and compile it
 # once.  Decompiling the result will of course yield a different
@@ -17,7 +16,7 @@ def test_1canonicalise_tutorials
   def test_2canonicalise_crystal
     canonicalise("crystal/crystal.sck", :source)
   end
-    
+
   def test_3canonicalise_adams
     %w{
       adv01
@@ -44,7 +43,7 @@ def test_3canonicalise_adams
         x[0] = ""
         options[:bug_tolerant] = true
       end
-      canonicalise("adams/#{x}.dat", :object, options) 
+      canonicalise("adams/#{x}.dat", :object, options)
     end
   end
 
@@ -76,12 +75,10 @@ def canonicalise(name, type, options = {})
 
   def compile(source, options)
     game = ScottKit::Game.new(options)
-    f = StringIO.new
-    withIO(nil, f) do
-      game.compile_to_stdout(nil, StringIO.new(source)) or
-        raise "couldn't compile"
-    end
-    f.string
+    output = StringIO.new
+    game.compile(output, nil, StringIO.new(source)) or
+      raise "couldn't compile"
+    output.string
   end
 
   def decompile(object, options)
diff --git a/test/test_compile.rb b/test/test_compile.rb
index 5bb3d29..5560103 100644
--- a/test/test_compile.rb
+++ b/test/test_compile.rb
@@ -1,7 +1,6 @@
 require 'test/unit'
 require 'scottkit/game'
 require 'stringio'
-require 'scottkit/withio'
 
 class TestCompile < Test::Unit::TestCase #:nodoc:
   EXPECTED = [
@@ -44,11 +43,9 @@ def test_parser
 
   def test_code_generator
     game = ScottKit::Game.new({})
-    f = StringIO.new
-    withIO(nil, f) do
-      game.compile_to_stdout("games/test/crystal.sck") or
-        raise "couldn't compile crystal.sck"
-    end
-    assert_equal(f.string, File.read("games/test/crystal.sao"))
+    compiled_game = StringIO.new
+    game.compile(compiled_game, "games/test/crystal.sck") or
+      raise "couldn't compile crystal.sck"
+    assert_equal(compiled_game.string, File.read("games/test/crystal.sao"))
   end
 end
diff --git a/test/test_play.rb b/test/test_play.rb
index 4602b33..0ca5f95 100644
--- a/test/test_play.rb
+++ b/test/test_play.rb
@@ -1,20 +1,19 @@
 require 'test/unit'
 require 'scottkit/game'
 require 'stringio'
-require 'scottkit/withio'
 
 class TestPlay < Test::Unit::TestCase #:nodoc:
   def test_play_tutorial7; play("t7"); end
   def test_play_crystal; play("crystal"); end
 
   def play(name)
-    game = ScottKit::Game.new({ :read_file =>
-                                "games/test/#{name}.solution",
-                                :random_seed => 12368, :no_wait => true })
+    game = ScottKit::Game.new(read_file: "games/test/#{name}.solution",
+                              output: StringIO.new, random_seed: 12368,
+                              no_wait: true)
     game.load(IO.read("games/test/#{name}.sao"))
-    f = StringIO.new
-    withIO(nil, f) { game.play }
+    game.play
+
     expected = File.read("games/test/#{name}.transcript")
-    assert_equal(expected, f.string)
+    assert_equal(expected, game.output.string)
   end
 end
diff --git a/test/test_playadams.rb b/test/test_playadams.rb
index de091c4..4efbcd5 100644
--- a/test/test_playadams.rb
+++ b/test/test_playadams.rb
@@ -2,7 +2,6 @@
 require 'scottkit/game'
 require 'stringio'
 require 'digest/md5'
-require 'scottkit/withio'
 
 class TestPlayAdams < Test::Unit::TestCase #:nodoc:
   def test_play_adams
@@ -15,13 +14,12 @@ def play(name)
     gamefile = "games/adams/#{name}.dat"
 
     if(File::readable?(gamefile))
-      game = ScottKit::Game.new({ :read_file =>
-                                  "games/test/adams/#{name}.solution",
-                                  :random_seed => 12368, :no_wait => true })
+      game = ScottKit::Game.new(output: StringIO.new,
+                                read_file: "games/test/adams/#{name}.solution",
+                                random_seed: 12368, no_wait: true )
       game.load(IO.read gamefile)
-      f = StringIO.new
-      withIO(nil, f) { game.play }
-      digest = Digest::MD5.hexdigest(f.string)
+      game.play
+      digest = Digest::MD5.hexdigest(game.output.string)
       expected = File.read("games/test/adams/#{name}.transcript.md5").chomp
       assert_equal(expected, digest)
     else
diff --git a/test/test_save.rb b/test/test_save.rb
index ff7693e..a6e174e 100644
--- a/test/test_save.rb
+++ b/test/test_save.rb
@@ -1,30 +1,28 @@
 require 'test/unit'
 require 'scottkit/game'
 require 'stringio'
-require 'scottkit/withio'
 
 class TestSave < Test::Unit::TestCase #:nodoc:
   # Can't use a setup() method here as the two test-cases need the
   # games to be initialised with different options.
 
   def test_save_crystal
-    game = ScottKit::Game.new({ :random_seed => 12368, :echo_input => true })
+    game = ScottKit::Game.new(random_seed: 12368, echo_input: true,
+                              input: File.new("games/test/crystal.save-script"),
+                              output: StringIO.new)
     game.load(IO.read("games/test/crystal.sao"))
-    withIO(File.new("games/test/crystal.save-script"), 
-           File.new("/dev/null", "w")) do
-      game.play()
-    end
+    game.play()
     assert_equal(File.read("TMP"), File.read("games/test/crystal.save-file"))
     File.unlink "TMP"
   end
 
   def test_resave_crystal
-    game = ScottKit::Game.new({ :random_seed => 12368, :echo_input => true,
-        :restore_file => "games/test/crystal.save-file" })
+    game = ScottKit::Game.new(random_seed: 12368, echo_input: true,
+                              input: StringIO.new("save game\nTMP"),
+                              output: StringIO.new,
+                              restore_file: "games/test/crystal.save-file")
     game.load(IO.read("games/test/crystal.sao"))
-    withIO(StringIO.new("save game\nTMP"), File.new("/dev/null", "w")) do
-      game.play()
-    end
+    game.play()
     assert_equal(File.read("TMP"), File.read("games/test/crystal.save-file"))
     File.unlink "TMP"
   end
diff --git a/test/withio_test.rb b/test/withio_test.rb
deleted file mode 100755
index 3f2b6c9..0000000
--- a/test/withio_test.rb
+++ /dev/null
@@ -1,31 +0,0 @@
-#!/usr/local/bin/ruby -w
-
-# Run as: echo Bart Lisa | ./withio_test.rb && echo == && cat /tmp/xcv
-# Expecting the output:
-#	first line is 'Bart Lisa'
-#	saved line 'Eric'
-#	died in withIO: divided by 0
-#	saved line was 'Eric'
-#	==
-#	first line was 'Bart Lisa'
-#	oldout is of class IO
-
-require 'stringio'
-require 'scottkit/withio'
-
-saved = nil
-begin
-  line = gets
-  puts "first line is '#{line.chomp}'"
-  withIO(StringIO.new("Eric\nthe"), File.new("/tmp/xcv", "w")) do
-    |oldin, oldout|
-    puts "first line was '#{line.chomp}'"
-    puts "oldout is of class #{oldout.class}"
-    saved = gets
-    oldout.puts "saved line '#{saved.chomp}'"
-    puts 1/0
-  end
-rescue Exception => e
-  puts "died in withIO: #{e}"
-end
-puts "saved line was '#{saved.chomp}'"