Wrap all compiler assignments in begin/end

This is much safer than having to explicitly call "wrap" in a potential
large amount of places.

lib/oga/ruby/node.rb

@@ -56,11 +56,14 @@ module Oga
       ##
       # Returns an assignment node.
       #
+      # This method wraps assigned values in a begin/end block to ensure that
+      # multiple lines of code result in the proper value being assigned.
+      #
       # @param [Oga::Ruby::Node] other
       # @return [Oga::Ruby::Node]
       #
       def assign(other)
-        Node.new(:assign, [self, other])
+        Node.new(:assign, [self, other.wrap])
       end
 
       ##

lib/oga/xpath/compiler.rb

@@ -1358,49 +1358,6 @@ module Oga
       #
       # Everything else is processed the usual (and possibly slower) way.
       #
-      # The variables used by this operator are assigned a "begin" block
-      # containing the actual result. This ensures that each variable is
-      # assigned the result of the entire block instead of the first expression
-      # that occurs.
-      #
-      # For example, take the following expression:
-      #
-      #     10 = 10 = 20
-      #
-      # Without a "begin" we'd end up with the following code (trimmed for
-      # readability):
-      #
-      #     eq_left3 = eq_left1 = ...
-      #
-      #     eq_left2 = ...
-      #
-      #     eq_left1, eq_left2 = to_compatible_types(eq_left1, eq_left2)
-      #
-      #     eq_left1 == eq_left2
-      #
-      #     eq_left4 = ...
-      #
-      #     eq_left3 == eq_left4
-      #
-      # This would be incorrect as the first boolean expression (`10 = 10`)
-      # would be ignored. By using a "begin" we instead get the following:
-      #
-      #     eq_left3 = begin
-      #       eq_left1 = ...
-      #
-      #       eq_left2 = ...
-      #
-      #       eq_left1, eq_left2 = to_compatible_types(eq_left1, eq_left2)
-      #
-      #       eq_left1 == eq_left2
-      #     end
-      #
-      #     eq_left4 = begin
-      #       ...
-      #     end
-      #
-      #     eq_left3 == eq_left4
-      #
       # @param [AST::Node] ast
       # @param [Oga::Ruby::Node] input
       # @param [TrueClass|FalseClass] optimize_first
@@ -1415,8 +1372,8 @@ module Oga
         left_ast  = try_match_first_node(left, input, optimize_first)
         right_ast = try_match_first_node(right, input, optimize_first)
 
-        initial_assign = left_var.assign(left_ast.wrap)
+        initial_assign = left_var.assign(left_ast)
-          .followed_by(right_var.assign(right_ast.wrap))
+          .followed_by(right_var.assign(right_ast))
           .followed_by { yield left_var, right_var }
       end
 

spec/oga/ruby/generator_spec.rb

@@ -21,7 +21,11 @@ describe Oga::Ruby::Generator do
       val    = Oga::Ruby::Node.new(:lit, %w{10})
       assign = var.assign(val)
 
-      @generator.on_assign(assign).should == 'number = 10'
+      @generator.on_assign(assign).should == <<-EOF
+number = begin
+  10
+end
+      EOF
     end
   end
 

spec/oga/ruby/node_spec.rb

@@ -34,7 +34,11 @@ describe Oga::Ruby::Node do
       node  = left.assign(right)
 
       node.type.should == :assign
-      node.to_a.should == [left, right]
+
+      node.to_a[0].should == left
+
+      node.to_a[1].type.should    == :begin
+      node.to_a[1].to_a[0].should == right
     end
   end