OpenEuphoria

Re: Try/Catch

• Posted by dcuny Feb 12, 2015
• 4341 views

You're not going to try to provide a value for a bad index. Rather, you'll try to structure the program so that it can recover from an action that failed because of an exception.

What that recovery is depends on the application. For example, here's the "recovery" on an attempt to open a file that failed because of some exception:

... 
case OPEN_FILE then 
   try 
      open_file(fileName) 
   catch e 
      alert("The file " & fileName & " could not be opened. " & e[EXCEPTION_MESSAGE]) 
   end try 
... 

On the other hand, a developer might simply try to prevent their program from dying by wrapping the top level:

-- handle events until exitProgram is true 
while not exitProgram do 
   -- is there an event to process? 
   if eventInQueue() then 
      try 
         -- handle the event 
         process( getEvent() ) 
      catch e 
         alert(e[EXCEPTION_MESSAGE]) 
      end try 
   else 
      -- release the cpu 
      pause() 
   end if 
end while 

It's up to the developer to decide at what level it is appropriate to try to catch exceptions. Generally, these will be fairly high up - not at the low level that you're focusing on.

- David