# frozen_string_literal: true
$expect_verbose = false
class IO
# call-seq:
# IO#expect(pattern,timeout=9999999) -> Array
# IO#expect(pattern,timeout=9999999) { |result| ... } -> nil
#
# The +expect+ library adds instance method IO#expect,
# which is similar to the
# {TCL expect extension}[https://www.tcl.tk/man/expect5.31/expect.1.html].
#
# To use this method, you must require +expect+:
#
# require 'expect'
#
# 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.
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
end
