[Interest] Args

[Till Oliver Knoll]

> Am 08.05.2017 um 01:48 schrieb Igor Mironchik <igor.mironchik at gmail.com>:
> 
> Hi,
>>>> Using exceptions in arguments parser is something that just cannot be justified.
>>>> 
>>> Why not?
>> Even in the danger of starting a huge debate about "exceptions vs return error code" here are my thoughts about it:
>> 
>> Exceptions should just be used for... well, /exceptional/ cases.
>> 
>> So what would be an "exceptional case" for a command line parser then? Certainly not wrongly provided arguments. Humans tend to misspell words all the time, so that's "the norm": business as usual for a command line parser to validate the input and inform the user appropriately (with a usage help, similar spelled commands etc.). Nothing which cries "exception!" here IMHO.
>> 
>> The only thing I could think of in a 10 second brainstorming which could be considered "exceptional" is when e.g. "stdin" (or some socket even from which to read commands, but even this would be a bordercase, as it could be considered "normal" that a socket cannot be opened) cannot be opened for reading (which is somewhat a constructed example, as arguments are usually passed as input parameters to main() anyway - but you get the idea).
>> 
>> The internet is full of articles - and opinions - about when to use exceptions, and when not (and we haven't even touched the topic of "unchecked vs checked exceptions" - at least in the Java camp that's all the rage ;)).
> 
> I will not start that holly war about what you said.... :) I just say that I will think about more and more user friendly messages on wrong user input.

Hold on: the one (exceptions vs return error codes) has /nothing/ to do with the other (user-friendly error messages). Just to be on the same page here...
 
> I wanted to simplify a life of a developer and a user of console application. But developer will be informed about "errors" through the exceptions.

Yes, your intentions were clear. But did you just read what I wrote about /when/ to use exceptions?

In fact, you're not - necessarily - simplifying "the life of a developer" by using exceptions. Au contraire, you force them to use patterns like RAII (which is mostly a good thing by itself), think about whether their code is "exception-safe" etc.

There is probably a reason why completely new languages like Swift come completely without exception handling - which raises interesting questions (pun intended), as the main "GUI framework" (Cocoa/ObjC based) still uses - and throws - exceptions then and when... but that's yet another story ;)

Cheers,
  Oliver