Cannot specify negative number as command option value

As of version 0.40.0, it doesn’t appear possible to specify a negative number as a command option.

Assuming I define a command that takes a decimal value as a command option, and that I want to pass a negative number value, neither of the following works:

mycommand -a -1.50
mycommand -a "-1.50"

Both attempts fail with this error Not a valid name for a short option. It appears that the command option parsing logic thinks that the -1.50 is supposed to be a command option.

I would expect that the quotes at least would effectively escape the numeric value. Is this a bug, or am I missing something?

Thanks.

[jouniheikniemi]

While I do feel that implementing an existing standard is always a good thing, I also feel that implementing POSIX is a bit too much, here.

Oh I’m certainly not ready to write a full POSIX compliance PR either, now 😅

Thanks! My next week is busyish, but I’ll take a look once I have a moment.

[nils-a]

@jouniheikniemi I’ll try to answer all your questions.

[…] Spectre.Cli used to say it is “extremely opinionated”, so what’s its opinion here?

That would be @patriksvensson opinion of things. I think there’s no fully written down version of it 😄

Do you have a master plan here?

Again, nothing that’s written down or anything.

Currently, options follow the following guidelines:

• option names can only be letters or digits (char.IsLetterOrDigit)
• no option can start with a digit
• each option can have one short name (starting with -, followed by exactly one character) or one long name (starting with --) or both.
• if options have a value, that value needs to be passed after the option, separated by either a space ( ) or equal (=) sign. (I think passing a colon (:) is also possible)

(I hope this is all of them, and I did not forget anything.)

I personally prefer POSIX/GNU parsing in everything I do

While I do feel that implementing an existing standard is always a good thing, I also feel that implementing POSIX is a bit too much, here. (And, I personally dislike -afoo for -a foo and -xvjf for -x -v -j -f.)

So, to summarize the above, currently -1 and --11 are not valid options, and they were planned as such. At the same time, I see the inability to pass -1 as an argument to an option using e.g. --foo -1 instead of --foo=-1 as a bug.