preferred line width may be set

ext/psych/emitter.c

@@ -460,6 +460,32 @@ static VALUE indentation(VALUE self)
     return INT2NUM(emitter->best_indent);
 }
 
+/* call-seq: emitter.line_width
+ *
+ * Get the preferred line width.
+ */
+static VALUE line_width(VALUE self)
+{
+    yaml_emitter_t * emitter;
+    Data_Get_Struct(self, yaml_emitter_t, emitter);
+
+    return INT2NUM(emitter->best_width);
+}
+
+/* call-seq: emitter.line_width = width
+ *
+ * Set the preferred line with to +width+.
+ */
+static VALUE set_line_width(VALUE self, VALUE width)
+{
+    yaml_emitter_t * emitter;
+    Data_Get_Struct(self, yaml_emitter_t, emitter);
+
+    yaml_emitter_set_width(emitter, NUM2INT(width));
+
+    return width;
+}
+
 void Init_psych_emitter()
 {
     VALUE psych     = rb_define_module("Psych");
@@ -483,6 +509,8 @@ void Init_psych_emitter()
     rb_define_method(cPsychEmitter, "canonical=", set_canonical, 1);
     rb_define_method(cPsychEmitter, "indentation", indentation, 0);
     rb_define_method(cPsychEmitter, "indentation=", set_indentation, 1);
+    rb_define_method(cPsychEmitter, "line_width", line_width, 0);
+    rb_define_method(cPsychEmitter, "line_width=", set_line_width, 1);
 
     id_write = rb_intern("write");
 }

lib/psych/visitors/yaml_tree.rb

@@ -54,7 +54,7 @@ def push object
           version = @options[:version].split('.').map { |x| x.to_i }
         else
           version = [1,1]
-        end if @options[:version]
+        end if @options.key? :version
 
         @emitter.start_document version, [], false
         accept object

test/psych/test_emitter.rb

@@ -10,6 +10,12 @@ def setup
       @emitter = Psych::Emitter.new @out
     end
 
+    def test_line_width
+      assert_equal 0, @emitter.line_width
+      assert_equal 10, @emitter.line_width = 10
+      assert_equal 10, @emitter.line_width
+    end
+
     def test_set_canonical
       @emitter.canonical = true
       assert_equal true, @emitter.canonical