Error message not helpfull

[janwilmans]

phooey.exe -h Docopt usage string could not be parsed Mismatched '['

message has no linenr, nor any text/tokens of line offending line. I will add the reproduction scenario as soon as I figure out what line it is, by binary search elimination.

[janwilmans]

found it; the -a line is the offending line, or at least, when it is removed, the error disappears. In fact it is not matching with the [-a (value)] , that actually doesn't make much sense and should probably have been [-a value]

static const char USAGE[] =
R"(DebugviewConsole )" VERSION_STR
R"(
    Usage: 
        DebugviewConsole [-a (value)] [-i <pattern>, --include <pattern>]... [-e <pattern>, --exclude <pattern>]... 

    Options:
      -h --help             Show this screen
      -a value              auto-newline [default: true]  // offending line
      -i <pattern>, --include <pattern>     include filter, may be specified multiple times
      -e <pattern>, --exclude <pattern>     exclude filter, may be specified multiple times

)";

[jaredgrubb]

Yes, the error messages are not helpful. This is a limitation that we inherit from the docopt sources. I'd like to see this fixed, but I think it's a more global problem that just the C++ implementation. I'm always open to suggestions on this.

[janwilmans]

Ok, so what is efficient, should I try to improve this in the python implementation of docopt and you can pull it in / convert that somehow?

I guess better error messages would require more script/detailed parsing or analysis of the parser output ?

[indianakernick]

It seems like almost all errors fall through to this point. Simply printing out all the arguments that the user passed isn't useful. That line might as well be throw DocoptArgumentError("Error");. Though, to be fair, the python implementation has the same problem so maybe I'm complaining in the wrong place!

It seems like fixing this would involve rewriting a lot of code (and breaking parity because of better error messages). I really like this library and I'm almost willing to do that myself but I don't think it would be worth the effort (plus I'm pretty lazy!).

---

This issue has lead me to doing these sort of checks on my end (which sort of defeats the purpose of docopt a little bit). For example, I use Usage: test [--a --b] as the help text passed to docopt and Usage: test [--a | --b] as help text shown to the user. Then if the user writes test --a --b, I can check if both options are present and print out --a must be mutually exclusive with --b. I've also used this technique to get around #55. I really wish I didn't have to do this.

[jaredgrubb]

I would love to see better error messages but I think it would be a lot of work -- almost a full rewrite. I would be open to it, but I think it's a big effort. This repo was mostly a port of the Python one, which (as you note) suffers from the same problem.

If someone wants to start that, I would be willing to work with them to do it in a way that is going to be successful.