[Omake] Confirmation dialog

[Andrew Gacek]

I want to guard one of my omakefile targets with a confirmation
dialog. For example, I want something like the following

% omake guarded-target
Warning. Running this command will do XYZ. Types YES to confirm.

Is there a straightforward way to do this? I've tried using input-line
as follows

  RESULT = $(input-line $(stdin))

But this gives the error: "Non digestible value". I've also tried
using scan() but it keeps looping forever rather than reading a single
line of input.

Thanks for you help,
Andrew