how to properly run a program and supply command line arguments?

[mortax]

i have a tiny program but the only way i am able to run it is using wing compile, e.g.:

[univac]$ cat echo.main.w 
let main = (args: Array<str>) => {
  log(args.at(0));
  log(args.at(1));
};

main(["first", "two"]);
[univac]$ wing compile echo.main.w --platform sim           
first
two
[univac]$ wing compile echo.main.w                             
first
two

in may real program, i had to resort to JavaScript to generate output without a newline and to exit with a non-zero return code. i do not see any way to have args: Array<str>? from the command line passed to a program, e.g.:

[univac]$ cat echo.main.w 
let main = (args: Array<str>?) => {
  if let args = args {
    log(args.at(0));
    log(args.at(1));
  }
};
[univac]$ wing compile echo.main.w     
[univac]$ wing compile echo.main.w -- one two
[univac]$ 

i assume that simply isn't possible right now. am i correct?

(of course i do realize i'm, subverting the overall purpose of Wing to create a simple CLI program. nonetheless...)

[staycoolcall911]

Hi @mortax, I believe we currently don't have a straight forward way to reference arbitrary command line arguments on Wing code. You're more than welcome to open an issue with your use case.

As a workaround, if env variables could help in your case, that is actually supported in Wing and you can reference env variables in the following way:

1. Import util library by adding bring util; at the head of your main.w.
2. util.env() or util.tryEnv() will give you the value of the env variable (docs).

[mortax]

thanks @staycoolcall911. using environment variables is cleaner that my current method so i'll give that a try. i'll open an issue as soon as i can.

[staycoolcall911]

Thank you, appreciated. Please let us know how it goes

[mortax]

shoot: i never replied. i used something like this:

let var args = MutArray<str>[];

if let env = Json.tryParse(util.tryEnv("WING_ARGS")) {
  for v in Json.values(env) {
    args.push(v.asStr());
  }
}

which worked very well. thanks.