Hi,
A try statement will "catch" an occurrence of a "throw". The throw
can be performed anywhere in the engine or from one of your own
handlers/functions. If an "exception" is "'thrown" and there is no
"try" structure in place, then an execution error will be generated
(e.g. the Engine or IDE catches the error). In the case below, Mark
didn't care what the exception actually was, he just wanted it to be
caught so as not to cause an execution error or corrupt or the
"forecolor". Just using the try without the corresponding catch is
allowed and is just shorthand for:
try
do something
catch myError
end try
You can use try/catch and throw in your own scripts to make it easier
to handle errors or make it easier to debug. Say you had a number of
functions that all call each other and any one of them can generate
an error, there are two main ways of handling this:
1. Returning Error Codes.
on mouseUP
put Func1() into myErrorCode
if myErrorCode != 0 then
answer "ErrorCode:" && myErrorCode
exit mouseUp
end if
function Func1
if <something isn't right> then return 1
put Func2() into myErrorCode
if myErrorCode != 0 then return myErrorCode
return 0
end Func1
function Func2
if <something isn't right> then return 2
put Func3() into myErrorCode
if myErrorCode != 0 then return myErrorCode
return 0
end Func2
function Func3
if <something isn't right> then return "3"
return 0
end Func3
2 Using Throw and Catch.
on mouseUP
try
get Func1()
catch myErrorCode
answer "ErrorCode:" && myErrorCode
exit mouseUp
end try
end mouseUp
function Func1
if <something isn't right> then throw 1
get Func2() myErrorCode
return 0
end Func1
function Func2
if <something isn't right> then throw 2
get Func3()
return 0
end Func2
function Func3
if <something isn't right> then throw 3
return 0
end Func3
Hope this Helps
All the Best
Dave
On 13 Apr 2006, at 08:28, Graham Samuel wrote:
In the very interesting discussion on Custom Properties, Mark
Wieder introduced this example
setProp NewValue pValue
try
if pValue < 0 then
set the foreColor of me to "red"
else
set the foreColor of me to empty
end if
end try
put pValue into me
end NewValue
I think I get the idea, but Mark, why did you use 'try'? It would
not occur to me to do this - indeed I don't think I've ever used
'try', which if I understand correctly, allows the script to
capture an error rather than handing it to the RR engine: but that
involves 'catch' doesn't it? Is there any advantage to using 'try'
the way you did?
Just curious - there's so much I don't know!
Graham
----------------------------------------------------------------------
-----
Graham Samuel / The Living Fossil Co. / UK and France
_______________________________________________
use-revolution mailing list
use-revolution@lists.runrev.com
Please visit this url to subscribe, unsubscribe and manage your
subscription preferences:
http://lists.runrev.com/mailman/listinfo/use-revolution
_______________________________________________
use-revolution mailing list
use-revolution@lists.runrev.com
Please visit this url to subscribe, unsubscribe and manage your subscription
preferences:
http://lists.runrev.com/mailman/listinfo/use-revolution
