diff --git a/lib/imbecile.rb b/lib/imbecile.rb
index 2099602..f25d22e 100644
--- a/lib/imbecile.rb
+++ b/lib/imbecile.rb
@@ -21,7 +21,7 @@ module Imbecile
 
     def run(input_file, output_file)
       begin
-        grammar = Grammar.new(input_file)
+        grammar = Grammar.new(File.read(input_file))
       rescue Error => e
         $stderr.puts e.message
         return 2
diff --git a/lib/imbecile/grammar.rb b/lib/imbecile/grammar.rb
index 7c7c9cc..3d4ebff 100644
--- a/lib/imbecile/grammar.rb
+++ b/lib/imbecile/grammar.rb
@@ -7,10 +7,10 @@ module Imbecile
     # @return [String, nil] Class name.
     attr_reader :classname
 
-    def initialize(input_file)
+    def initialize(input)
       @tokens = {}
       @rules = {}
-      File.read(input_file).each_line.each_with_index do |line, line_index|
+      input.each_line.each_with_index do |line, line_index|
         line = line.chomp
         line_number = line_index + 1
         if line =~ /^\s*#/