CODEWITHSUNDEEP
rustclap
ditoslav
ditoslav

Reputation: 4872

What are valid characters and how to escape in clap.rs arguments?

I want to pass in some shape or form a dictionary/map/object into my clap app. I can preprocess the dict to turn it into some csv or whatever. My problem is that I cannot find in clap docs which characters are valid for the argument values and how to escape them. Is this unrelated to clap and instead shell specific?

Can I pass something like

myApp --dicty="a=1,b=3,qwe=yxc"

?

Upvotes: 0

Views: 570

Answers (1)

Masklinn
Masklinn

Reputation: 42492

Is this unrelated to clap and instead shell specific?

Mostly, yes. clap is going to get whatever arguments the shell has determined and will parse that.

However clap has built-in support for value sets, from the readme:

  • Supports multiple values (i.e. -o <val1> -o <val2> or -o <val1> <val2>)
  • Supports delimited values (i.e. -o=val1,val2,val3, can also change the delimiter)

If that's not sufficient, then you'll have to define dicty as a String, you will receive the string a=1,b=3,qwe=yxc (I don't think you'll receive the quotes) then you'll have to parse that yourself, either by hand (regex/split/...) or with something more advanced (e.g. the csv crate though that's likely overkill).

That seems like a somewhat odd option value though.

FWIW structopt (which builds upon clap to provide a more declarative UI, and should be part of Clap 3) doesn't exactly have support for that sort of things but can be coerced into it relatively easily: https://github.com/TeXitoi/structopt/blob/master/examples/keyvalue.rs

With some modifications would allow something like

myApp -D a=1 -D b=3 -D que=yxc

or (though see comments in linked snippet for limitations)

myApp -D a=1 b=3 que=yxc

to be collected as a vec![("a", "1"), ("b", "3"), ("que", "yxc")] from which creating a hashmap is trivial.

Upvotes: 2

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