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If you used to use Expect version 2 (any version written before

September '91) you will find that the current version of Expect (3)

introduced minor but significant incompatibilities.

The HISTORY file describes these briefly.  They are described at

length in the man page.

I'm sorry if you feel annoyed at the incompatibilities, but Expect has

been out for a year and a half, Tcl even longer.  Both Tcl and Expect

are using this as a last chance to make significant changes, so that

we will not disturb even more users in the future.

There is no automated conversion procedure (although see note below)

for Expect or even raw Tcl.  For now, I suggest that you not bother

fixing things that already work - just keep the old Expect around.

The binary isn't very big after all.  If you do write a translation

script, let me know.  Thanks.

Of course, I felt obligated to convert the examples distributed with

expect.  I did this by hand while writing the new version itself,

partly as an aid but mostly to test lots of variations.  In 90% of the

scripts, all I had to do was change:

(changes due to Tcl)

        'index' to 'lindex'

        'range' to 'lrange'

        'length' to 'llength'

        'print' to 'send_user' or 'puts' depending on how you use it

        'function .... c' with '[join [function [split string ""]] ""]'

(changes due to Expect)

        'expect_match' to 'expect_out(buffer)'

        'set match_max' to 'match_max' (perhaps with -d flag)

        '*' to '-re .+'

If anyone wants to write a script to do this, note the pitfalls:

1) functions and variables do not share the same namespace, so it is a

inappropriate to just globally rename things.

A number of optimizations can be made:

1) If you are doing multiple split/joins, you should probably cache the

split string.

2) Virtually all uses of scan are unnecessary now, due to exec's automatic

stripping of terminating newlines, and expect's support of regexps.

3) String manipulation can be reduced or avoided entirely if you use

expect -re.

4) exec is no longer necessary to retrieve environment variables, since

they can now be retrieved from $env.

5) If you have been really anal about testing for timeout and eof, you

can dramatically reduce the size of your scripts by using expect_before

and expect_after.  This is more efficient, as well, since those actions

are only parsed once.