Re: Try/Catch
- Posted by ghaberek (admin) Feb 18, 2015
- 4166 views
Spock said...
Ok. I think I got this right:
1 Add delete_routine() to libraries - cleanup happens automatically when atom leaves scope
Or
2 Use try/catch/finally - manually call cleanup routine
Let's say I'm too lazy to do 1 (or it'd be really awkward since my libraries usually return integers (object IDs) not pointers). So how will I know which cleanup routines to call in finally in 2?
Spock
That's entirely up to you, isn't it? You'd have to clean up whatever you started, correct?
The finally statement simply affords you that opportunity, and it is entirely optional.
atom x
try
-- get our resource to work with
x = get_resource()
-- do several things with the resource
-- that might throw an exception here
step_1( x )
step_2( x )
step_3( x )
step_4( x )
step_5( x )
catch e
-- ERROR HANDLING CODE GOES HERE --
finally
-- our resource will always be freed here
-- (unless we encounter a fatal error)
if object( x ) then
free_resource( x )
end if
end try
Now compare that code to this...
atom x = get_resource()
if error_code != 0 then
-- ERROR HANDLING CODE GOES HERE --
return -- just quit
end if
step_1( x )
if error_code != 0 then
-- ERROR HANDLING CODE GOES HERE --
goto "cleanup"
end if
step_2( x )
if error_code != 0 then
-- ERROR HANDLING CODE GOES HERE --
goto "cleanup"
end if
step_3( x )
if error_code != 0 then
-- ERROR HANDLING CODE GOES HERE --
goto "cleanup"
end if
step_4( x )
if error_code != 0 then
-- ERROR HANDLING CODE GOES HERE --
goto "cleanup"
end if
step_5( x )
if error_code != 0 then
-- ERROR HANDLING CODE GOES HERE --
goto "cleanup"
end if
label "cleanup"
free_resource( x )
I would prefer the first option, but right now I am bound to the second.
-Greg
