Expect¶

The expect module handles simple expect(1)-like behaviour. The two main functions are exp-case and exp-send.

One difference in behaviour from expect(1) is that exp-timeout is -1 by default (as Don Libes has said he should have done himself).

simple-expect.idio¶

import expect

spawn nslookup

(exp-case
 (:re "> $" #t))

;; add a \r to the end of the sent string
exp-send "server 8.8.8.8" :cr #t

(exp-case
 (:re "> $" #t))

exp-send "www.google.com.\r"

ipv4_addrs := #n
ipv6_addrs := #n

;; wait for the answer section
(exp-case
 ("answer:" #t))

(exp-case
 (:re "Address:[[:space:]]+([.:[:xdigit:]]+)" {
   addr := nth r.1 0
   (pattern-case
    addr
    ("*.*" {
      ipv4_addrs = pair addr ipv4_addrs
    })
    ("*:*" {
      ipv6_addrs = pair addr ipv6_addrs
    }))
   (exp-continue)
 })
 (:re "> $" {
   exp-send "exit\r"
 }))

if (not (null? ipv4_addrs)) {
  printf "the IPv4 addrs are %s\n" ipv4_addrs
}

if (not (null? ipv6_addrs)) {
  printf "the IPv6 addrs are %s\n" ipv6_addrs
}

$ idio simple-expect
spawn nslookup
server 8.8.8.8.8
Default server: 8.8.8.8
Address: 8.8.8.8#53
www.google.com.m.
Server:         8.8.8.8
Address:        8.8.8.8#53

Non-authoritative answer:
Name:   www.google.com
Address: 172.217.169.36
Name:   www.google.com
Address: 2a00:1450:4009:818::2004
the IPv4 addrs are ("172.217.169.36")
the IPv6 addrs are ("2a00:1450:4009:818::2004")

Functions¶

spawn runs its arguments as a command in a pseudo-terminal device and sets spawn-id.

exp-case has exp-case-before and exp-case-after siblings.

The clauses to these are

(str-kw* str body) where str-kw can be:
- :re to treat str as a regexp
- :gl to treat str as a glob-style pattern
- :ex to treat str as an exact string
- :icase to use a case-insensitive match
(term-kw body) where term-kw can be:
- :eof to match if End of File is indicated
- :timeout to match if the timeout is reached
- :all to always match

If a match occurs the body is invoked with spawn-id, r (the REG_VERBOSE regexec results) and prefix (the contents of spawn-id’s buffer before the match) variables in scope.

exp-continue and exp-break are available in body.

exp-wait will try to drain spawn-id and potentially call exp-close.

Last built at 2024-12-21T07:11:29Z+0000 from 77077af (dev) for Idio 0.3