* ext/psych/emitter.c (initialize): allow a configuration object to be

  passed to the constructor so that mutation isn't required after
  instantiation.

* ext/psych/lib/psych/handler.rb: add configuration object

* ext/psych/lib/psych/visitors/emitter.rb: use configuration object if
  extra configuration is present.

2 files changed, 26 insertions, 4 deletions

diff --git a/lib/psych/handler.rb b/lib/psych/handler.rb
index a2aa6bb..d3b9963 100644
--- a/lib/psych/handler.rb
+++ b/lib/psych/handler.rb
@@ -11,6 +11,21 @@ module Psych
   # See Psych::Parser for more details
   class Handler
     ###
+    # Configuration options for dumping YAML.
+    class DumperOptions
+      attr_accessor :line_width, :indentation, :canonical
+
+      def initialize
+        @line_width  = 0
+        @indentation = 2
+        @canonical   = false
+      end
+    end
+
+    # Default dumping options
+    OPTIONS = DumperOptions.new
+
+    ###
     # Called with +encoding+ when the YAML stream starts.  This method is
     # called once per stream.  A stream may contain multiple documents.
     #
diff --git a/lib/psych/visitors/emitter.rb b/lib/psych/visitors/emitter.rb
index 30db176..c886e50 100644
--- a/lib/psych/visitors/emitter.rb
+++ b/lib/psych/visitors/emitter.rb
@@ -2,10 +2,17 @@ module Psych
   module Visitors
     class Emitter < Psych::Visitors::Visitor
       def initialize io, options = {}
-        @handler = Psych::Emitter.new io
-        @handler.indentation = options[:indentation] if options[:indentation]
-        @handler.canonical = options[:canonical] if options[:canonical]
-        @handler.line_width = options[:line_width] if options[:line_width]
+        opts = [:indentation, :canonical, :line_width].find_all { |opt|
+          options.key?(opt)
+        }
+
+        if opts.empty?
+          @handler = Psych::Emitter.new io
+        else
+          du = Handler::DumperOptions.new
+          opts.each { |option| du.send :"#{option}=", options[option] }
+          @handler = Psych::Emitter.new io, du
+        end
       end
 
       def visit_Psych_Nodes_Stream o