Look up "throw" in the dictionary. Apparently you can use it with or without a
try/catch structure. It's a way to generate an error outside the scope of
engine generated script errors.
try
if not (there is a file
"/Users/MyProfile/Library/Preferences/MyAppCriticalPreferences.plist") then
throw "missing_prefs_file"
end if
catch theError
answer theError & cr & "I have to quit now."
quit
end try
I know it works because I just accidentally quit my Livecode session!
This could be used in conjunction with a central error handling user defined
command or function. Let's say you have a command called "on customError
pErrorNum". In it you have a switch statement for pErrorNum which handles each
error differently. Some errors you want to simply inform the user and reset the
form. Others may be critical ones and you have to bail out gracefully.
try
if not (there is a file
"/Users/MyProfile/Library/Preferences/MyAppCriticalPreferences.plist") then
throw "missing_prefs_file"
end if
catch theError
customError -666
end try
on customError pErrorNum
switch pErrorNum
case 666
put "A critical error has occurred. The application will now exit."
into theMsg
put true into isCritical
case 777
put "A non-critical error has occurred. Please try again."
put false into isCritical
end switch
answer theMsg as sheet
if isCritical then
cleanup -- I am not going to write a fictitious cleanup routine!
quit
end if
end customError
Bob
On Mar 23, 2012, at 10:08 AM, Jim Hurley wrote:
> Mark,
>
> Yes! I agree with you about "throw".
>
> Do you, or dose anyone, have an example that shows the use of the "throw"
> command in conjunction with the "try-catch" structure?
>
> Jim
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