Mini Shell

# frozen_string_literal: false
#
#   shell/builtin-command.rb -
#       $Release Version: 0.7 $
#       $Revision: 53141 $
#       by Keiju ISHITSUKA(keiju@ruby-lang.org)
#
# --
#
#
#

require "shell/filter"

class Shell
  class BuiltInCommand<Filter
    def wait?
      false
    end
    def active?
      true
    end
  end

  class Void < BuiltInCommand
    def initialize(sh, *opts)
      super sh
    end

    def each(rs = nil)
      # do nothing
    end
  end

  class Echo < BuiltInCommand
    def initialize(sh, *strings)
      super sh
      @strings = strings
    end

    def each(rs = nil)
      rs =  @shell.record_separator unless rs
      for str  in @strings
        yield str + rs
      end
    end
  end

  class Cat < BuiltInCommand
    def initialize(sh, *filenames)
      super sh
      @cat_files = filenames
    end

    def each(rs = nil)
      if @cat_files.empty?
        super
      else
        for src in @cat_files
          @shell.foreach(src, rs){|l| yield l}
        end
      end
    end
  end

  class Glob < BuiltInCommand
    def initialize(sh, pattern)
      super sh

      @pattern = pattern
    end

    def each(rs = nil)
      if @pattern[0] == ?/
        @files = Dir[@pattern]
      else
        prefix = @shell.pwd+"/"
        @files = Dir[prefix+@pattern].collect{|p| p.sub(prefix, "")}
      end
      rs =  @shell.record_separator unless rs
      for f in @files
        yield f+rs
      end
    end
  end

  class AppendIO < BuiltInCommand
    def initialize(sh, io, filter)
      super sh
      @input = filter
      @io = io
    end

    def input=(filter)
      @input.input=filter
      for l in @input
        @io << l
      end
    end

  end

  class AppendFile < AppendIO
    def initialize(sh, to_filename, filter)
      @file_name = to_filename
      io = sh.open(to_filename, "a")
      super(sh, io, filter)
    end

    def input=(filter)
      begin
        super
      ensure
        @io.close
      end
    end
  end

  class Tee < BuiltInCommand
    def initialize(sh, filename)
      super sh
      @to_filename = filename
    end

    def each(rs = nil)
      to = @shell.open(@to_filename, "w")
      begin
        super{|l| to << l; yield l}
      ensure
        to.close
      end
    end
  end

  class Concat < BuiltInCommand
    def initialize(sh, *jobs)
      super(sh)
      @jobs = jobs
    end

    def each(rs = nil)
      while job = @jobs.shift
        job.each{|l| yield l}
      end
    end
  end
end