gistfile1.rb

require 'optparse'
require 'scanner/scanner'

module SC
  class SimpleCompilerError < RuntimeError
  end

  class CommandOptionError < RuntimeError
  end

  class SimpleCompiler
    def initialize(args)
      begin
        @opts  = parse_args(args)
        @input = get_input
      rescue CommandOptionError => ex
        raise SimpleCompilerError, ex.to_s
      end
    end

    def parse_args(args)
      opts = { :phase => :unspecified, :input => :stdin }
      optparser = OptionParser.new

      optparser.banner = "./sc [-s] [filename]"

      optparser.on("-s", "invokes the scanner") do
        opts[:phase] = :scanner
      end

      begin
        optparser.parse!(args)
      rescue OptionParser::ParseError
        raise CommandOptionError, optparser.to_s
      end

      case
        when args.length == 1 then opts[:input] = args[0]
        when args.length > 1 then raise CommandOptionError, optparser.to_s
      end

      raise CommandOptionError, optparser.to_s if (opts[:phase] == :unspecified)

      return opts
    end

    def get_input
      io =
        if @opts[:input] == :stdin
          $stdin
        else
          File.new(@opts[:input])
        end

      input = io.read
      io.close

      return input
    end

    def run
      case
        when @opts[:phase] == :scanner then run_scanner
      end
    end

    def run_scanner

    end

    public  :run
    private :get_input, :parse_args, :run_scanner
  end
end