Improve scripting UI

[crispinb]

There are really 3 types of UIs for terminal use:

1. the classic cli, with all necessary data supplied as flags, for one-shot interactionless use
2. interactive, prompting the user linewise for missing info (eg. npm create ...)
3. tui

cvcap currently is an awkward blend of cli/interactive - mostly interactive but sort-of cli with the -q flag. Currently however this mode just fails when info is missing (eg there's no defualt list), with no capacity to provide the missing data as part of the invocation.

The standard approach to dealing with cli vs interactive is to blend them, using an ever more complex combination of flags - eg -y to skip prompts. But which prompts? This could be sorted out with positional -ys or some other complex combination of flags.

But I wonder if it might be simpler (and less tied to posix/unix) to just keep the two cases separate.

-q (or maybe something like --noninteractive to make it triply clear) can flick cvcap into a different mode, where all data must be provided to avoid a nonzero exit. To make this even clearer, and avoid having to mess more than I want to with clap, my current thought is for that data to be provided en bloc in a structure. Inline JSON perhaps, or perhaps search for a way that needs less "-escaping (does this even matter for scripting/programmatic use?)

[crispinb]

see https://clig.dev/#interactivity for standard guidelines, notably:

• check stdin is a tty for interactivity
• offer a --no-input option to suppress interactivity
• use -q

What's the case for --no-input without -q?