module Sexpr
  module Matcher
    class Terminal
      include Matcher

      attr_reader :value

      def initialize(value)
        @value = value
      end

      def inspect
        "(terminal #{value.inspect})"
      end

      def match?(sexp)
        terminal_match?(sexp)
      end

      def eat(sexp)
        match?(sexp.first) ? sexp[1..-1] : nil
      end

      private

      def terminal_match?(term)
        case @value
        when Regexp
          @value === term rescue false
        when TrueClass, FalseClass, NilClass
          @value == term
        end
      end

    end # class Terminal
  end # module Matcher
end # module Sexpr