Customize array flag functionality

[infalmo]

Take a program that takes input of the following form:

multidiff --input 1.in 2.in 3.in --output 1.out 2.out 3.out

Now, the flags can be achieved using .Flags().StringSlice(...) which would take the input in format:

multidiff --input=1.in,2.in,3.in --output=1.out,2.out,3.out

However, imagine there were many (say 100) matching input and output files. Using tab completion lists all files, but uses a space to seperate them (instead of a comma, that pflag uses).
So, my question is, is there any way to achieve the above, without writing platform dependent shell scripts?

[cornfeedhobo]

@infinitepr0 I can only think of specifying the flag multiple times

[infalmo]

What about something like

multidiff --input-begin *.in --input-end --output-begin *.out --output-end

I don't think this is widely used, so I guess it would be better to not create a non-conventional method.

[cornfeedhobo]

@infinitepr0 For what it's worth. I'm still thinking about this. If I think of something elegant, I'll be sure to revisit this.

[hoshsadiq]

Fwiw the --flag value1 value2 and --flag value1,value2 isn't really used anywhere but in spf13/pflag. Usually arguments are either positional or flags, or flags followed by their value. In my opinion a stringslice should only accept --flag val1 --flag val2 (or its shorthand equivalent). The CSV option is especially painful as you cannot have a value with commas in it. E.g. let's say you're rebuilding packers var option (--var key=value), if value is allowed to have commas in it, it's harder to achieve this.

I've never come across a CLI tool that expects multiple inputs and multiple outputs. Take mv for example. It has unlimited source files/directories, but one target file/directory. Same with cp.

[cornfeedhobo]

@hoshsadiq I agree. This CSV parsing causing more trouble than it's worth. I'm not sure ripping it out would work out for the cobra users though. Might be worth investigating.

In fact, another issue was submitted upstream that relates to this.