Sorry, but this change makes no sense. What problem are you trying to solve?

@asterite #5291
I would have liked to provide the actual file name in the error, but that information isn't available, and fixing that issue would involve a major amount of re-write that could break other people's use cases, so I've avoided it thus far. Let me know if you see any other issues here :)

That issue is about showing suggestions for when you pass a flag to the compiler, and the flag is not found. Here you are changing option parser (which can be used in any crystal program, not just the compiler), to suggest that the flag should be passed Ina different way. And that makes no sense at all.

@benglewis OptionParser is used by countless Crystal applications, not just by the compiler. You can't add a very compiler-specific behaviour to such a general class. This did-you-mean flag needs to go into the compiler's command handling.

Oh.

@benglewis I've run into this myself, especially when I was just starting Crystal. I would have loved to have seen a nice error like the one you are suggesting so I wouldn't have to ask for help.

@straight-shoota or @asterite could you provide a link to the file or some other guidance so that this suggestion could be shown in the correct place? That may help @benglewis or someone else make the changes to add this feature in the right place

This is the place to look: https://github.com/crystal-lang/crystal/blob/master/src/compiler/crystal/command.cr#L170

The original proposal is that if you run a program with crystal foo.cr --flag and that flag doesn't exist in the program foo.cr, then you'd get an error saying you should invoke it like crystal foo.cr -- --flag. To me, that seems impossible to implement. Or, well, it's this PR, but it's not correct to show that error because you can run the program as . /foo once it's compiled.

And I wouldn't go down the route of adding a flag that is present if you run the program through crystal, just for this error message.

There should simply be an answer to this in stackoverflow.com, problem solved.

https://stackoverflow.com/questions/45117892/passing-cli-arguments-to-excutables-with-go-run

I didn't read the original issue so that was my mistake.

I don't think it is a high priority, but I do think that Crystal will be more loved if more helpful errors can be shown to users. It's such a delight when languages/libraries give me a hint that saves even just a few minutes.

So maybe it would be hard, but if someone adds it, I think it would be a great addition! Especially because people may not know what to google for.

My thought would be that it only applies when using the crystal tool and if you give it an option it doesn't understand it shows what it shows now, plus an additional help saying something like: "If you meant to access this flag in your program use -- #{options}. Much like what the author did, but just for the crystal command and not in OptionParser. Maybe that's what you already imagined, but I wanted to get it written down just in case.

What do you think? If someone does implement it, would it be worth adding to save time and give users that extra bit of help so they don't break their flow?

As usual, if someone wants to implement it, go ahead. After all I'm no longer approving/merging PRs :-P

Also note that if you have a program that just does ARGV[0], so it doesn't use OptionParser, then there's simply no way to detect this. And if you only add this knowledge to OptionParser, if you use another shard to parse options then it won't work (unless that shard also adds a similar solution).

So I don't think the original issue makes much sense. That's just my opinion, though, but again, this seems impossible to implement.

Really, crystal foo.cr --flag should send --flag to foo.cr.

Options before the filename should go the compiler, options after should go to the file. As well as being less confusing, this also makes it possible to do #!/usr/bin/env crystal in scripts.

Thank you for the discussion guys.

I am in agreement with @RX14 here. I think that simply considering the order of the flags would be the most logical version to me as a user, but I do understand that that may not fit with the strategy for Crystal. If a conclusion can be reached on what to implement, I would be happy to try as a complete newbie to Crystal :)