On Wed, 28 Aug 2002, Ed Dana wrote: > Yes. But the value that I was trying to assign Fred was the error that > was to occur when I attempted my action.
you capture that error from 'try >> either error? err: try[1 / 0 ][true][false] == true >> err ** Math Error: Attempt to divide by zero ** Near: 1 / 0 >> either error? err: try[1 / 1][true][false] == false >> err == 1 > More accurately, I have written a couple of daemons, that execute a > command that I pass to it as a parameter. I wanted the daemon to send > out an email if it could not execute the action it was assigned. > Something like this (where Action is the variable that holds the > statement to be executed: > If Error? Error: Try [ Do Action] [ Send Warning email ] > Realizing that Try is similar to Do, I even used: > If Error? Error: Try [ Action] [ Send Warning email ] > been doing something similar daily for years should not be a problem > The first executed without issue, making me think that everything was > executing OK; it wasn't. The second gave me the "no value" error. > > But this is why I'm confused: If try is to be used to help trap errors, > why does it care if a value is set or not? That's why I pointed out that > I got the error when issuing a "write" command. If anything needed to be > trapped, it was that. How else can I tell if a file is not there, or I > don't have access permission, or the file system is too full, etc? I agree that current behavior does not lead me down the path of least astonishment. I would expect err: try[prin ""] to pass quietly and 'err to have the value it would have after a unset 'err that is: >> error? unset 'err == false prolly should send it to feedback. however as a umm.. hack! you could add a constant (anything but an error!) to the end of your 'try block 'try will return the constant if it gets to it without encountering an error first. err: none either error? err: try[ (1 / 0 ) "no-err"][true][false] == true >> err ** Math Error: Attempt to divide by zero ** Near: 1 / 0 >> err: none either error? err: try[ (print 1 ) "no-err"][true][false] 1 == false >> err == "no-err" >> err: none either error? err: try[ (1 ) "no-err"][true][false] == false >> err == "no-err" >> either error? err: try[ make error! "boo" "no-err"][true][false] == true >> err ** User Error: boo ** Near: make error! "boo" "no-err" >> -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with "unsubscribe" in the subject, without the quotes.
