[tuify] create a new binary that allows strings to be passed in and the selection is returned as an int (index of what the user chose)

[nazmulidris]

Use case

• A script runs and it needs the user to choose between 3 choices.
• These choices are all in the form of strings that are surrounded by quotes.
• The choice of the user can be in the form of the index of the string array (0..length-1), or -1, meaning user chose nothing (exited).
• The binary name for this is rtc, since there's already a binary called rt that handles a different use case.

Example of using this in a fish script

The output of:

rtc "setup database" "run migrations" "create new migrations and run them"

Could be one of the following, in the form of an exit code:

• -1 => this means that the user chose nothing (they pressed Esc)
• 0 => the user chose the 1st option "setup database"
• 1 => the user chose the 2nd option "run migrations"
• 2 => the user chose the 3rd option "create new migrations and run them"

Additionally the string that is selected can be stored in an environment variable $user_selection.

This can then be used in a fish script to do something like this:

echo (set_color blue)Welcome to db setup!(set_color normal)
echo (set_color green)Please select one from the following:(set_color normal)
rtc "setup database" "run migrations" "create new migrations and run them"

if test $status -eq 0
  echo You chose \"setup database\"
end

if test $status -eq 1
  echo You chose \"run migrations\"
end

if test ($user_selection) = "create new migrations and run them"
  echo You chose the 3rd item
end

if test $status -eq -1
  echo Exiting script
end

Advanced use cases

In the previous example, only a single selection is made by the user. Perhaps a flag can be passed that would allow them to make multiple choices, eg: --multiple.

In this case the exit code could be -2, which means that the user has made multiple selections.

Two environment variables could be used to capture the selection indices and text:

1. $user_selection_indices => this might contain a space delimited sequence of numbers, eg: 0 1
2. $user_selection_choices => this might contain a space delimited sequence of strings, eg: "foo" "bar" "baz"

Here's an example of the syntax for this use case:

rtc --multiple "setup database" "run migrations" "create new migrations and run them"

Real world use case

The rust-scratch repo has a sql crate which has a fish script that can benefit from this. That script has a complex user flow that would benefit from using this rtc instead of the built-in fish function read.