2 files changed, 17 insertions, 7 deletions
diff --git a/src/thue/program.cr b/src/thue/program.cr
index c59780b..f449f5a 100644
--- a/src/thue/program.cr
+++ b/src/thue/program.cr
@@ -6,8 +6,16 @@ class Thue::Program
   end
 
   def interpret
-    something = @parser.parse
-    puts something
+    rules, state = @parser.parse
+
+    loop do
+      r = rules.find { |r| r.matches?(state) }
+      break if r.nil?
+
+      state = state.sub(r.pattern, r.replacement)
+    end
+
+    puts state
   end
 end
 
diff --git a/src/thue/rule.cr b/src/thue/rule.cr
index 34c2396..cd45adc 100644
--- a/src/thue/rule.cr
+++ b/src/thue/rule.cr
@@ -1,14 +1,16 @@
 require "./thue.cr"
 
 abstract struct Thue::Rule
-  @pattern : Regex
+  @regex : Regex
 
-  def initialize(pattern : String)
-    @pattern = Regex.new(pattern)
+  getter pattern : String
+
+  def initialize(@pattern : String)
+    @regex = Regex.new(Regex.escape(@pattern))
   end
 
   def matches?(str : String) : Bool
-    str.matches?(@pattern)
+    str.matches?(@regex)
   end
 
   abstract def replacement : String
@@ -26,7 +28,7 @@ end
 
 struct Thue::InputRule < Thue::Rule
   def replacement : String
-    gets
+    gets || ""
   end
 end