src/thue/rule.cr


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require "./thue.cr"

abstract struct Thue::Rule
  @regex : Regex

  getter pattern : String

  def initialize(@pattern : String)
    @regex = Regex.new(Regex.escape(@pattern))
  end

  def matches?(str : String) : Bool
    str.matches?(@regex)
  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