Closes Feature Request: https://github.com/jmbannon/ytdl-sub/issues/743
Subscriptions support using presets as keys, and using keys to set override variables as values.
For example:
```
tv_show:
only_recent:
[News]:
"Breaking News": "https://www.youtube.com/@SomeBreakingNews"
[Tech]:
"Two Minute Papers": "https://www.youtube.com/@TwoMinutePapers"
```
Will create two subscriptions named "Breaking News" and "Two Minute Papers", equivalent to:
```
"Breaking News":
preset:
- "tv_show"
- "only_recent"
overrides:
subscription_indent_1: "News"
subscription_name: "Breaking News"
subscription_value: "https://www.youtube.com/@SomeBreakingNews"
"Two Minute Papers":
preset:
- "tv_show"
overrides:
subscription_indent_1: "Tech"
subscription_name: "Two Minute Papers" subscription_value: "https://www.youtube.com/@TwoMinutePapers"
```
You can provide as many parent presets in the form of keys, and subscription indents as ``[keys]``.
This can drastically simplify subscription definitions by setting things you want configurable like so in your
parent preset:
```
presets:
tv_show_name:
overrides:
tv_show_name: "{subscription_name}"
url: "{subscription_value}"
genre: "{subscription_indent_1}"
```
NOTE!!!
Changing your subscription name from 'legacy' subscriptions will need their download archive file migrated to a new name. A future update will assist in this migration process. Either wait until then or, if you consider yourself a ytdl-sub expert, keep a backup of your subscription file before migrating.
