Getopt and optparse vs argparse

[Nodd (Joseph Martinot-Lagarde)]

@storchaka

Usually, if option -f has a required parameter, -f -b means option -f with argument -b. But in argparse this is an error, missed argument for option -f. You should write -f-b (without space) to pass argument -b for option -f. But this does not work if the value starts with =, because -f=-b mens option -f with argument -b. You should write -f==-b or -f =-b to pass argument =-b for option -f. The latter does not work if the value starts with -, and the former is unexpected, because it differs from the behavior of other Unix/Linux programs.

Also, the workaround dous not work at all for multi-argument options.

This is at the core of argparse – they assume that the user missing an argument for option is much more probable that the user passing an argument that starts with -. argparse does not work without such assumption.

I had this problem multiple times when passing negative numbers as arguments. It’s a pain to explain the workarounds to users.