module Sexpr
  class Terminal
    include Element

    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 Sexpr