Denizen Script Language Explanations


Language Explanations explain components of Denizen in a more direct and technical way than The Beginner's Guide.


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NameProcedure Script Containers
DescriptionProcedure 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 spawns an entity into the world,
you would likely end up with a *lot* of unintentional entity spawns.
Some tags will be read multiple times when theoretically ran once,
in some circumstances a tag read might even be based on user input! (Particularly if you ever make use of the '.parsed' tag,
or the list.parse/filter/sort_by_number tags).
Imagine if for example, a tag can be read when users input a specific custom command,
and a clever user finds out they can type "/testcommand 32 <proc[spawn_entity].context[creeper]>"
to spawn a creeper ... that would be a major problem!
In general, maximum caution is the best for situations like this... simply *never* make a procedure
that executes external changes. 


Proc_Script_Name:

    type: procedure

    # Optionally specify definition names to use with the 'context' input of the proc tag.
    definitions: def|names|here

    script:

    # Put any logic, then determine the result.
    - determine 5
GroupScript Container System
Sourcehttps://github.com/DenizenScript/Denizen-Core/blob/master/src/main/java/com/denizenscript/denizencore/scripts/containers/core/ProcedureScriptContainer.java#L9