I have a question about the functionality of argparse. I use argparse for custom functions and it's great, but sometimes I'd like to move the use of argparse and supplemental code into a separate function and use it there to reduce boilerplate / visual noise.
This is a partial example of what I'd like to do:
function A
set --local options ... # some definition.
argparse_wrapper --name A $options -- $argv; or return 1
end
instead of
function A
set --local options ... # some definition.
argparse --name A $options -- $argv; or return 1
# Code validating flags set by argparse in some way that argparse is unable to do,
# i.e. validation that requires values from two flags (so f/flag!script would not
# work).
#
# Or, changing flag names to names more appropriate inside the function.
#
# Other boilerplate related to options, but
# unrelated to the purpose of the function.
#
end
But, I'm unable to set values inside of a function and transfer those values seamlessly to the caller. As in, argparse sets values in the outer scope (the function calling argparse), but I'm unable to do the same with a custom argparse wrapper of my own. At least, I'm unsure of how to do so if there is a clean way. In particular, argparse can set local variables in its outer scope, and I want to keep that functionality in the supposed argparse wrapper. Is that possible?
I'm the person who designed and implemented argparse. The approach I recommend is the one you'll find in the share/functions/fish_opt.fish module. Execute the argparse in the function that implements the command. Define a helper function with the --no-scope-shadowing flag to give it direct access to the vars in the parent function. Then call that function to validate the args (or do whatever is needed) after argparse returns.