Re: error handling

[Jonathan Rees <Rees@YALE.ARPA>]

    Date:    Thu, 12 Apr 84 13:06:04 EST
    From:    Stanley Letovsky <Letovsky>

    I have this problem of needing to take some action when an error occurs,
    regardless of why. I am in a situation where I have acquired the display,
    and then I am running user-supplied code. If an error occurrs, I have
    to release the display immmediately -- before even writing an error
    message -- or the system will get highly screwed up. Is there any
    way - released or unreleased - to get control immediately upon an error?

The U editor uses an unreleased condition system.  You should look
at the sources; ask Nat Mishkin or Jim Philbin for pointers.  TC also
uses the condition system; look at TRANSDUCE.T.

That system has serious deficiencies and is waiting to be redesigned.
The redesign will be along the lines of the Common Lisp condition
system, but hopefully simpler.