Remove parser switching duplication

lib/liquid/parser_switching.rb

@@ -0,0 +1,30 @@
+module Liquid
+  module ParserSwitching
+    def parse_with_selected_parser(markup)
+      case @options[:error_mode] || Template.error_mode
+      when :strict then strict_parse_with_error_context(markup)
+      when :lax    then lax_parse(markup)
+      when :warn
+        begin
+          return strict_parse_with_error_context(markup)
+        rescue SyntaxError => e
+          @warnings ||= []
+          @warnings << e
+          return lax_parse(markup)
+        end
+      end
+    end
+
+    private
+    def strict_parse_with_error_context(markup)
+      strict_parse(markup)
+    rescue SyntaxError => e
+      e.message << markup_context(markup)
+      raise e
+    end
+
+    def markup_context(markup)
+      " in \"#{markup.strip}\"" 
+    end
+  end
+end