Hairy Pixels via fpc-pascal <fpc-pascal@lists.freepascal.org> schrieb am Do., 25. Mai 2023, 04:32:
> > > > On May 24, 2023, at 8:46 PM, Michael Van Canneyt via fpc-pascal < > fpc-pascal@lists.freepascal.org> wrote: > > > > I see no problem, I am used to this. > > > > This is Pascal, you need to manage your memory and hence your > references, this is true even in the absence of exceptions: In your example > you would > > also need to remember to remove your instance from the list after you > free > > it, even if there are no exceptions. > > My example is still not good. The problem I have is that once exceptions > are used in a program calling any function now has a side effect of > completely exiting the calling function so you need to be paranoid and wrap > everything in try blocks just in case. A new added burden for manual memory > management. > I'd say you're over thinking things. The main part is that you protect locally allocated memory (be it class instances or plain pointers) using "try... finally" and make sure other memory is for example deallocated in a destructor. If that's ensured then you can have exceptions bubble up as far as you're comfortable. E.g. in a LCL application if an exception is raised somewhere inside an event handler and it isn't explicitly handled there it will in the end result in a shown error dialog. Assuming all resources along the way were guarded by resource protection blocks life can just go on then when the user closes the dialog. In essence: always protect the resources and only handle an exception explicitly if you can provide the user with a better error message than what the exception already provides or have can give them the ability to correct something. Why is this better than handling errors as values like a normal function > result? > This would mean that every function (and procedure) that can fail or calls a routine that can fail would have to provide some kind of error channel and the user would then have to check this, cluttering their code with error checks (just look at how correctly error checked code with classic Pascal I/O looks with all the checks for IOResult). With exceptions you can simply concentrate on the meaty parts of your algorithms or business logic and let the language itself deal with the exceptional (pun intended). Regards, Sven
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