Using conditional statements inside 'expect'

Question

I need to automate logging into a TELNET session using expect, but I need to take care of multiple passwords for the same username.

Here\'s the flow

Answer 1

With a bit of bashing I found a solution. Turns out that expect uses a TCL syntax that I'm not at all familiar with:

#!/usr/bin/expect
set pass(0) "squarepants"
set pass(1) "rhombuspants"
set pass(2) "trapezoidpants"
set count 0
set prompt "> "
spawn telnet 192.168.40.100
expect {
  "$prompt" {
    send_user "successfully logged in!\r"
  }
  "password:" {
    send "$pass($count)\r"
    exp_continue
  }
  "login incorrect" {
    incr count
    exp_continue
  }
  "username:" {
    send "spongebob\r"
    exp_continue
  }
}
send "command1\r"
expect "$prompt"
send "command2\r"
expect "$prompt"
send "exit\r"
expect eof
exit

Hopefully this will be useful to others.