method

expect

Ruby latest stable (v2_5_5) - 0 notes - Class: IO

expect(pat,timeout=9999999) public

Reads from the IO until the given pattern matches or the timeout is over.

It returns an array with the read buffer, followed by the matches. If a block is given, the result is yielded to the block and returns nil.

When called without a block, it waits until the input that matches the given pattern is obtained from the IO or the time specified as the timeout passes. An array is returned when the pattern is obtained from the IO. The first element of the array is the entire string obtained from the IO until the pattern matches, followed by elements indicating which the pattern which matched to the anchor in the regular expression.

The optional timeout parameter defines, in seconds, the total time to wait for the pattern. If the timeout expires or eof is found, nil is returned or yielded. However, the buffer in a timeout session is kept for the next expect call. The default timeout is 9999999 seconds.

Show source

# File ext/pty/lib/expect.rb, line 33
  def expect(pat,timeout=9999999)
    buf = ''.dup
    case pat
    when String
      e_pat = Regexp.new(Regexp.quote(pat))
    when Regexp
      e_pat = pat
    else
      raise TypeError, "unsupported pattern class: #{pat.class}"
    end
    @unusedBuf ||= ''
    while true
      if not @unusedBuf.empty?
        c = @unusedBuf.slice!(0)
      elsif !IO.select([self],nil,nil,timeout) or eof? then
        result = nil
        @unusedBuf = buf
        break
      else
        c = getc
      end
      buf << c
      if $expect_verbose
        STDOUT.print c
        STDOUT.flush
      end
      if mat=e_pat.match(buf) then
        result = [buf,*mat.captures]
        break
      end
    end
    if block_given? then
      yield result
    else
      return result
    end
    nil
  end

expect

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