Differences

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--- tutorial:command_redirects [2022/08/08 02:19] – created (migrated from [[tutorial:commands]]) solidblock
+++ tutorial:command_redirects [2024/04/15 06:46] (current) – [Chainable Commands] solidblock
@@ Line 1: / Line 1: @@
 ======= Command Redirects =======
-Redirects are Brigadier's form of aliases and subcommands.
+Redirects are Brigadier's form of aliases and subcommands. The ''redirect'' method takes a command node and an optional modifier of context. The command node can be a specific node after a registration of dispathcer, or just the root node.
 ===== Aliases =====
-Below is how Minecraft makes ''/msg'' have an alias of ''/tell'' and ''/w''.
+In vanilla Minecraft, ''/tell'' and ''/w'' are redirected to ''/msg'', which you can see in ''MessageCommand''.
+The example shows how ''/foo2'' redirects to ''/foo''.
 <code java [enable_line_numbers="true"]>
-public static void register(CommandDispatcher<ServerCommandSource> dispatcher) {
+public class ExampleMod implements ModInitializer {
-    LiteralCommandNode node = dispatcher
+  @Override
-      .register(literal("msg")
+  public void onInitialize() {
-        .then(argument("targets", EntityArgumentType.players())
+    CommandRegistrationCallback.EVENT.register((dispatcher, registryAccess, environment) -> {
-        .then(argument("message", MessageArgumentType.message())
+      final LiteralCommandNode<ServerCommandSource> fooNode = dispatcher.register(literal("foo")
-        .executes(context -> {... /* code ommited */ }))));
+          .executes(context -> {
+            context.getSource().sendFeedback(() -> Text.literal("Called /foo with no arguments"), true);
-    dispatcher.register(literal("tell")
-        .redirect(node)); // Alias 1, redirect to main command
+            return 1;
-    dispatcher.register(literal("w")
+          }));
-        .redirect(node)); // Alias 2, redirect to main command
+      dispatcher.register(literal("foo2").redirect(fooNode));
+    });
+  }
 }
 </code>
-The ''redirect'' tells brigadier to continue parsing the command at another command node.
+The ''redirect'' tells brigadier to continue parsing the command at another command node. That's to say, what's after the "foo2" node is right what's after the "foo" node.
+The redirection target may not always be the root node. Commans can be redirected to sub-nodes, including arguments.
 ===== Chainable Commands ======
-Commands such as ''/execute as @e[type=player] in the_end run tp ~ ~ ~'' are also possible because of redirects. Below is an example of a chainable command:
+Commands such as ''/execute as @e[type=player] in the_end run tp ~ ~ ~'' are also possible because of redirects.
+Let's first consider the vanilla ''/execute'' command. There is a node after the ''%%literal("execute")%%''. After dispatching subcommands, the dispatcher is redirected to that node (with some modifiers), making you possible to, after completing sub-command arguments, type whatever can be typed directly after ''/execute''. In the sub-command ''run'', the dispatcher is redirected to the root node (''dispatcher.getRoot()''), allowing you to type another complete command after the word "''run''".
+Below is an example of a chainable command:
 <code java [enable_line_numbers="true"]>
 LiteralCommandNode<ServerCommandSource> rootNode = dispatcher.register(literal("fabric_test"));
 LiteralCommandNode<ServerCommandSource> root1 = dispatcher.register(literal("fabric_test")
-    // You can register under the same literal more than once, it will just register new parts of the branch as shown below if you register a duplicate branch an error will popup in console warning of conflicting commands but one will still work.
+    // You can register under the same literal more than once, it will just register new parts
+    // of the branch as shown below if you register a duplicate branch an error will popup in
+    // console warning of conflicting commands but one will still work.
     .then(literal("extra")
         .then(literal("long")
@@ Line 37: / Line 49: @@
         .then(literal("command")
             .executes(ctx -> {
-                ctx.getSource().sendFeedback(Text.literal("Chainable Command"), false);
+                ctx.getSource().sendFeedback(() -> Text.literal("Chainable Command"), true);
                 return Command.SINGLE_SUCCESS;
-})));
+            })));
 </code>
-The ''redirect'' can also modify the ''CommandSource'' by use of a "redirect modifier", which is used as a lambda.
+The ''redirect'' can also modify the ''CommandSource'' by use of a "redirect modifier" (''SingleRedirectModifier<S>''), which is usually used as a lambda.
 <code java [enable_line_numbers="true"]>
-.redirect(rootNode, context -> {
+            .redirect(rootNode, context -> {
-    // When redirecting, modify the looking direction of the command source.
+                // When redirecting, modify the looking direction of the command source.
-    return ((ServerCommandSource) context.getSource()).withLookingAt(Vec3ArgumentType.getVec3(context, "pos"));
+                return context.getSource().withLookingAt(Vec3ArgumentType.getVec3(context, "pos"));
-})
+            })
 </code>
+:!: In the redirect modifier, only arguments after the redirected nodes can be used. Meanwhile, arguments before the redirect modifier cannot be used in subsequent redirections (if any) or the final execution.