Procedure script containers are used to define a script that can be ran through a tag.
Generally called via !tag proc or !tag proc.context.
The only required key is 'script:'.
Note that procedure scripts must NEVER change external state.
That is, a procedure script cannot change anything at all, ONLY determine a value.
Setting a flag, loading a YAML document, placing a block, etc. are all examples of external changes that are NOT allowed.
This restriction comes from two main reasons:
- Tags run in arbitrary conditions. They may be read asynchronously or in other weird circumstances that can result
in applied changes crashing your server or other unexpected side effects.
- Tags can run for a variety of reasons.
If you were to make a proc script 'spawn_entity' that actually...