Add Individual Formula for MainIndex

[wienans]

As some of the metrics are not as standardized to the main maintainability index i found it helpful to provide my own formula via CLI. To Calibrate it for my projects.

If the individual flag is given without formula it will calculate the classic index.

[priv-kweihmann]

@wienans I gave it another thought and maybe something like described here https://twosixtech.com/blog/hijacking-the-ast-to-safely-handle-untrusted-python/ would be useful. Using ast.parse and limiting the input tokens to a few known ones would lower my concerns regarding outside definable formulas. If you want you can give it a shot, likely I won't have the time to look into it before the end of this month

[wienans]

@priv-kweihmann i also found the ast library und thought about it. But at the end for my purpose need to parse the JSON output anyway and then I could calculate the index with my formular for calibration too. Maybe I will think about it and implement it. But at the end in case of safety calculating a non standard index via the output with a other Skript seems the correct option even if I first thought it would be nice to quickly change the formula in cli and make this also available for all.

[priv-kweihmann]

@priv-kweihmann i also found the ast library und thought about it. But at the end for my purpose need to parse the JSON output anyway and then I could calculate the index with my formular for calibration too. Maybe I will think about it and implement it. But at the end in case of safety calculating a non standard index via the output with a other Skript seems the correct option even if I first thought it would be nice to quickly change the formula in cli and make this also available for all.

sounds like the right way (tm) to me :-). Just in case I would welcome PRs describing this "post processing" as part of the README

[wienans]

Decision to not implement it and rather use the output json with additional script