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c-blake / cligen

Nim library to infer/generate command-line-interfaces / option / argument parsing; Docs at
https://c-blake.github.io/cligen/
ISC License
496 stars 23 forks source link

Custom exit code in case of parsing errors #184

Closed SirNickolas closed 3 years ago

SirNickolas commented 3 years ago

As far as I can see, cligen quits with code 1 if the user made a mistake in calling the CL interface:

https://github.com/c-blake/cligen/blob/34b21db967a1a24d700e101ee1f30cc6db862d63/cligen.nim#L1142-L1146

However, exit code 1 is commonly used as an “unsuccessful” return code, and the program would likely want to emit it itself rather than afforing it to the CLI framework. Many programs return 2 when their interface is misused. It would be nice to have an ability to do so as well. (Perhaps, even change the default to promote such practice?)

An article about a cute language that does error handling the right way.

c-blake commented 3 years ago

I think 1 (or maybe 255/-1) is the most common unsuccessful error code, which is often used only as a true-false thing by higher levels. I agree more detail can be nice, and I do sometimes do that myself.

However, among those programs who want that detail, I disagree there is some common "many programs" convention like 2 = CLI parse error. I think there is no common convention { I do not doubt you have seen >=2 programs with that convention :-) I just disagree a broad, realistic survey would find a better default than 1. }. That said, I am fine having some variable/ClCfg field to specify the code. I'm working on your other request first, though.

If you are in a hurry, I think you can write your own cligenQuit template between import and dispatch to override all that behavior if you want. It's only a 20 line template...

c-blake commented 3 years ago

So..there are several different situations where there is a parse error (basic 1-proc dispatch, subcommands, init object from CL), but all situations are really invalid/unparsable user input. So, I just called them all cgParseErrorExitCode. If you just set that integer variable (anywhere between import & dispatch) to whatever you want, e.g. 2, then that should work.

SirNickolas commented 3 years ago

That was fast. Thanks.