Expose name, lookups, and command flags from VariableLookup

lib/liquid/variable_lookup.rb

@@ -3,6 +3,8 @@ module Liquid
     SQUARE_BRACKETED = /\A\[(.*)\]\z/m
     COMMAND_METHODS = ['size'.freeze, 'first'.freeze, 'last'.freeze]
 
+    attr_reader :name, :lookups, :command_flags
+
     def self.parse(markup)
       new(markup)
     end

test/unit/variable_unit_test.rb

@@ -147,4 +147,16 @@ class VariableUnitTest < Minitest::Test
     var = Variable.new(%! name_of_variable | upcase !)
     assert_equal " name_of_variable | upcase ", var.raw
   end
+
+  def test_variable_lookup_interface
+    lookup = VariableLookup.new('a.b.c')
+    assert_equal 'a', lookup.name
+    assert_equal ['b', 'c'], lookup.lookups
+    assert_equal 0, lookup.command_flags
+
+    lookup = VariableLookup.new('a.first.size')
+    assert_equal 'a', lookup.name
+    assert_equal ['first', 'size'], lookup.lookups
+    assert_equal 0b11, lookup.command_flags
+  end
 end