From: matz@... (Yukihiro Matsumoto)
Date: 2002-02-19T12:25:11+09:00
Subject: Re: expect.rb vs Expect (Tcl)...

Hi,

In message "expect.rb vs Expect (Tcl)..."
    on 02/02/19, Hugh Sasse Staff Elec Eng <hgs@dmu.ac.uk> writes:

|Are there plans to improve this funtionality to allow one to expect on
|many patterns, performing actions as appropriate?

Don't expect too much for 36 lines of code.  Here's my own version of
expecter, that waits for many patterns.

class Expecter
  def initialize(timeout=nil, dynamic=nil)
    @timeout=timeout
    @action= {}
    @dynamic=dynamic
  end

  def on(pattern, action=lambda)
    @action[pattern] = action
  end

  def wait(on)
    keys = @action.keys
    while TRUE
#      fds = select([on], nil, nil, @timeout)
      fds = select([on], nil, nil)
      unless fds
	if @action['TIMEOUT']
	  @action['TIMEOUT'].call
	end
	return
      end
      break if fds.size == 0 or fds[0].size == 0
      line = on.gets
      break unless line
      print line
      for key in keys
	if line =~ key
	  @action[key].call(line)
	end
      end
      keys = @action.keys if @dynamic
    end
    if @action['EOF']
      @action['EOF'].call
    end
  end

  def expect(on)
    fds = select([on], nil, nil, @timeout)
    unless fds
      if @action['TIMEOUT']
	@action['TIMEOUT'].call
      end
      return
    end
    return if fds.size == 0 or fds[0].size == 0
    line = on.gets
    unless line
      if @action['EOF']
	@action['EOF'].call
      end
      return
    end
    print line
    for key in @action.keys
      if line =~ key
	@action[key].call(line)
      end
    end
  end
end

Usage:

expect = Expecter.new
expect.on(/NO CARRIER/) do
  exit 1
end
expect.on(/Exit/) do
  exit 1
end
expect.on(/Failed/) do
  exit 1
end
expect.on(/[^n]REDIAL ERROR/) do
  exit 1
end
f = open("|tail -n 0 -f /var/log/messages")
dial
expect.wait(f)