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Comment by curryhoward | Hacker News Reader

I'm guessing the comment was talking about examples like this:

    program -abcdefg.txt

Just from reading this, you can't tell where the flags end and the filename begins unless you have all the flags and their arities memorized.

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Worse than that, it adds an unstable convention to an otherwise stable interface. What if there used to be a, b flags and then they add a c flag? Who knows what your command does now. It's just bad all around.

It’s not unstable or ambiguous at all.

    -abcdefg.txt

In your hypothetical -b takes an argument which means it consumes all the characters following it. Anything following b is never interpreted as a flag. There is no danger of -c changing the parsing. Even if b takes an optional argument it still consumes all characters following it.

Ah, you are right.

That’s always true even before you talk about option combining.

    python scr.py -a -v

Interpreting this command correctly requires you to know that python passes everything after the first positional argument to the script.

    ansible play.yml -v

Where ansible itself consumes the -v argument.

It gets even worse with subcommands.

    sudo -k command -a subcommand -v

Options parsing is nice because the arity of options is always 0 or 1.

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