Command Trees

The CommandTree type and utilities in CommandUtils allow for creating much more readable command trees in kotlin.

We start by calling CommandTree.buildLiteral or CommandTree.createLiteral which return a LiteralArgumentBuilder or LiteralCommandNode respectively. This method takes a lambda of LiteralArgumentBuilder<S>.() -> Unit which allows us to put everything related to this tree inside the lambda.

fun createExampleCommand(): LiteralArgumentBuilder<CommandSourceStack> {
    return CommandTree.buildLiteral("example") {

    }
}

We can add suggestions, requirements, literal subcommands and add arguments:

fun createExampleCommand(): LiteralArgumentBuilder<CommandSourceStack> {
    return CommandTree.buildLiteral("example") {
        requiresPermission(PermissionLevel.GAMEMASTERS)
        argument("argument", StringArgumentType.string()) {
            requires { it.level.dimension() == Level.OVERWORLD }
            executes { /* Command logic */ }
        }
        
        literal("subcommand") {
            argument("subcommand-argument", StringArgumentType.string()) {
                suggests { _, b -> SharedSuggestionProvider.suggest(listOf("a", "b", "c"), b) }
                executes { /* Command logic */ }
            }
        }
        literal("other-subcommand") {
            // ...
        }
    }
}

Other than the structuring of the command tree, everything else is the same as brigadier.