4 ms·

You can also do this without any extra gems: EXCEPTIONS = [Foo::Exception, Bar::Exception] begin # whatever rescue *EXCEPTIONS => e #

by cheald 12y ago

You can also do this without any extra gems: EXCEPTIONS = [Foo::Exception, Bar::Exception] begin # whatever rescue *EXCEPTIONS => e # Handle any exception in the array end The checking based on exception text is great, though.

djur 12y ago
This definitely works, and I've done it a lot in the past (and still would if my requirements are simple enough), but there's a few useful things that toe_tag does that this doesn't. First, you can pass it an array of exception names, and it will ignore ones that aren't defined. This is really useful if you need to group together exceptions from multiple libraries that may or may not be loaded (this happens a lot if you're writing an app expected to work both in MRI and JRuby). You also don't need to know anything special about toe_tag's synthetic exception classes to use them. No splat operator needed. You can also combine exception groups into larger groups, which you couldn't do with nested arrays and splat.
- cheald 12y ago
  Oh, definitely. I didn't mean to diminish the cool things toe_tag does - I just tend to dislike the tendency for novices to just use gems to do things without understanding why they work, o I like to point out where solutions can be accomplished in bare Ruby. :) toe_tag sounds like a great tool for the toolbox, but if the need is "I want to rescue multiple exceptions at once in a DRY fashion", there's no magic needed.
  - djur 12y ago
    Understood and agreed, as a fellow "just use Ruby"-ist. Once you've done something a few dozen times or so by hand, you start thinking about whether it might be handy to have a library for it. But as someone who is employed to maintain and improve more than one Ruby app with more than 200 gem dependencies apiece, I can say with certitude that there is such a thing as going too far. I have actually found that even fairly experienced Ruby developers have a limited understanding of how Ruby exceptions work. Usually there's one or two gaps -- like not knowing that `rescue Exception` is a bad idea, or not knowing `rescue => err` works (as opposed to `rescue StandardError => err`), or that multiple rescues can be added to a single begin block (I've seen nested `begin...rescue` constructs for exactly that reason), or that `rescue A, B` works. Or what the return value of `begin...rescue...ensure` is. (Or that `begin...rescue` can take an `else`, which is another example of its shared behavior with `case...when`. I still have yet to see begin-else used in real code, though, and I wouldn't encourage it.) Thank you for the kind words!

by cheald 12y ago

djur 12y ago

This definitely works, and I've done it a lot in the past (and still would if my requirements are simple enough), but there's a few useful things that toe_tag does that this doesn't. First, you can pass it an array of exception names, and it will ignore ones that aren't defined. This is really useful if you need to group together exceptions from multiple libraries that may or may not be loaded (this happens a lot if you're writing an app expected to work both in MRI and JRuby). You also don't need to know anything special about toe_tag's synthetic exception classes to use them. No splat operator needed. You can also combine exception groups into larger groups, which you couldn't do with nested arrays and splat.

cheald 12y ago
Oh, definitely. I didn't mean to diminish the cool things toe_tag does - I just tend to dislike the tendency for novices to just use gems to do things without understanding why they work, o I like to point out where solutions can be accomplished in bare Ruby. :) toe_tag sounds like a great tool for the toolbox, but if the need is "I want to rescue multiple exceptions at once in a DRY fashion", there's no magic needed.
- djur 12y ago
  Understood and agreed, as a fellow "just use Ruby"-ist. Once you've done something a few dozen times or so by hand, you start thinking about whether it might be handy to have a library for it. But as someone who is employed to maintain and improve more than one Ruby app with more than 200 gem dependencies apiece, I can say with certitude that there is such a thing as going too far. I have actually found that even fairly experienced Ruby developers have a limited understanding of how Ruby exceptions work. Usually there's one or two gaps -- like not knowing that `rescue Exception` is a bad idea, or not knowing `rescue => err` works (as opposed to `rescue StandardError => err`), or that multiple rescues can be added to a single begin block (I've seen nested `begin...rescue` constructs for exactly that reason), or that `rescue A, B` works. Or what the return value of `begin...rescue...ensure` is. (Or that `begin...rescue` can take an `else`, which is another example of its shared behavior with `case...when`. I still have yet to see begin-else used in real code, though, and I wouldn't encourage it.) Thank you for the kind words!