1 files changed, 43 insertions, 0 deletions
diff --git a/src/thue/rule.cr b/src/thue/rule.cr
new file mode 100644
index 0000000..34c2396
--- /dev/null
+++ b/src/thue/rule.cr
@@ -0,0 +1,43 @@
+require "./thue.cr"
+
+abstract struct Thue::Rule
+  @pattern : Regex
+
+  def initialize(pattern : String)
+    @pattern = Regex.new(pattern)
+  end
+
+  def matches?(str : String) : Bool
+    str.matches?(@pattern)
+  end
+
+  abstract def replacement : String
+end
+
+struct Thue::NormalRule < Thue::Rule
+  def initialize(pattern : String, @replacement : String)
+    super(pattern)
+  end
+
+  def replacement : String
+    @replacement
+  end
+end
+
+struct Thue::InputRule < Thue::Rule
+  def replacement : String
+    gets
+  end
+end
+
+struct Thue::OutputRule < Thue::Rule
+  def initialize(pattern : String, @output : String)
+    super(pattern)
+  end
+
+  def replacement : String
+    print @output
+    return ""
+  end
+end
+