Support for return values other than ints with backwards-compatability

.gitignore

@@ -65,4 +65,7 @@ gradle-app.setting
 hs_err_pid*
 
 
-repo/
+repo/
+
+# vscode workspace settings
+.vscode

src/main/java/com/mojang/brigadier/Command.java

@@ -7,8 +7,8 @@
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
 
 @FunctionalInterface
-public interface Command<S> {
+public interface Command<S, R> {
     int SINGLE_SUCCESS = 1;
 
-    int run(CommandContext<S> context) throws CommandSyntaxException;
+    R run(CommandContext<S> context) throws CommandSyntaxException;
 }

src/main/java/com/mojang/brigadier/CommandDispatcher.java

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation and Serena Lynas. All rights reserved.
 // Licensed under the MIT license.
 
 package com.mojang.brigadier;
@@ -8,6 +8,9 @@
 import com.mojang.brigadier.context.CommandContextBuilder;
 import com.mojang.brigadier.context.SuggestionContext;
 import com.mojang.brigadier.exceptions.CommandSyntaxException;
+import com.mojang.brigadier.results.CommandResult;
+import com.mojang.brigadier.results.EmptyCommandResult;
+import com.mojang.brigadier.results.ListCommandResult;
 import com.mojang.brigadier.suggestion.Suggestions;
 import com.mojang.brigadier.suggestion.SuggestionsBuilder;
 import com.mojang.brigadier.tree.CommandNode;
@@ -62,7 +65,7 @@ public boolean test(final CommandNode<S> input) {
             return input != null && (input.getCommand() != null || input.getChildren().stream().anyMatch(hasCommand));
         }
     };
-    private ResultConsumer<S> consumer = (c, s, r) -> {
+    private ResultConsumer<S, Object> consumer = (c, s, r) -> {
     };
 
     /**
@@ -104,7 +107,7 @@ public LiteralCommandNode<S> register(final LiteralArgumentBuilder<S> command) {
      *
      * @param consumer the new result consumer to be called
      */
-    public void setConsumer(final ResultConsumer<S> consumer) {
+    public void setConsumer(final ResultConsumer<S, Object> consumer) {
         this.consumer = consumer;
     }
 
@@ -138,7 +141,7 @@ public void setConsumer(final ResultConsumer<S> consumer) {
      * @see #execute(ParseResults)
      * @see #execute(StringReader, Object)
      */
-    public int execute(final String input, final S source) throws CommandSyntaxException {
+    public Object execute(final String input, final S source) throws CommandSyntaxException {
         return execute(new StringReader(input), source);
     }
 
@@ -172,7 +175,7 @@ public int execute(final String input, final S source) throws CommandSyntaxExcep
      * @see #execute(ParseResults)
      * @see #execute(String, Object)
      */
-    public int execute(final StringReader input, final S source) throws CommandSyntaxException {
+    public Object execute(final StringReader input, final S source) throws CommandSyntaxException {
         final ParseResults<S> parse = parse(input, source);
         return execute(parse);
     }
@@ -203,7 +206,7 @@ public int execute(final StringReader input, final S source) throws CommandSynta
      * @see #execute(String, Object)
      * @see #execute(StringReader, Object)
      */
-    public int execute(final ParseResults<S> parse) throws CommandSyntaxException {
+    public Object execute(final ParseResults<S> parse) throws CommandSyntaxException {
         if (parse.getReader().canRead()) {
             if (parse.getExceptions().size() == 1) {
                 throw parse.getExceptions().values().iterator().next();
@@ -214,7 +217,7 @@ public int execute(final ParseResults<S> parse) throws CommandSyntaxException {
             }
         }
 
-        int result = 0;
+        Object result = new EmptyCommandResult();
         int successfulForks = 0;
         boolean forked = false;
         boolean foundCommand = false;
@@ -250,7 +253,7 @@ public int execute(final ParseResults<S> parse) throws CommandSyntaxException {
                                     }
                                 }
                             } catch (final CommandSyntaxException ex) {
-                                consumer.onCommandComplete(context, false, 0);
+                                consumer.onCommandComplete(context, false, new EmptyCommandResult());
                                 if (!forked) {
                                     throw ex;
                                 }
@@ -260,12 +263,12 @@ public int execute(final ParseResults<S> parse) throws CommandSyntaxException {
                 } else if (context.getCommand() != null) {
                     foundCommand = true;
                     try {
-                        final int value = context.getCommand().run(context);
-                        result += value;
+                        final Object value = context.getCommand().run(context);
                         consumer.onCommandComplete(context, true, value);
+                        result = CommandResult.combine(result, value);
                         successfulForks++;
                     } catch (final CommandSyntaxException ex) {
-                        consumer.onCommandComplete(context, false, 0);
+                        consumer.onCommandComplete(context, false, new EmptyCommandResult());
                         if (!forked) {
                             throw ex;
                         }
@@ -278,7 +281,7 @@ public int execute(final ParseResults<S> parse) throws CommandSyntaxException {
         }
 
         if (!foundCommand) {
-            consumer.onCommandComplete(original, false, 0);
+            consumer.onCommandComplete(original, false, new EmptyCommandResult());
             throw CommandSyntaxException.BUILT_IN_EXCEPTIONS.dispatcherUnknownCommand().createWithContext(parse.getReader());
         }
 

src/main/java/com/mojang/brigadier/ResultConsumer.java

@@ -6,6 +6,6 @@
 import com.mojang.brigadier.context.CommandContext;
 
 @FunctionalInterface
-public interface ResultConsumer<S> {
-    void onCommandComplete(CommandContext<S> context, boolean success, int result);
+public interface ResultConsumer<S, R> {
+    void onCommandComplete(CommandContext<S> context, boolean success, R result);
 }

src/main/java/com/mojang/brigadier/builder/ArgumentBuilder.java

@@ -15,7 +15,7 @@
 
 public abstract class ArgumentBuilder<S, T extends ArgumentBuilder<S, T>> {
     private final RootCommandNode<S> arguments = new RootCommandNode<>();
-    private Command<S> command;
+    private Command<S, ?> command;
     private Predicate<S> requirement = s -> true;
     private CommandNode<S> target;
     private RedirectModifier<S> modifier = null;
@@ -43,12 +43,12 @@ public Collection<CommandNode<S>> getArguments() {
         return arguments.getChildren();
     }
 
-    public T executes(final Command<S> command) {
+    public <R> T executes(final Command<S, R> command) {
         this.command = command;
         return getThis();
     }
 
-    public Command<S> getCommand() {
+    public Command<S, ?> getCommand() {
         return command;
     }
 

src/main/java/com/mojang/brigadier/context/CommandContext.java

@@ -28,7 +28,7 @@ public class CommandContext<S> {
 
     private final S source;
     private final String input;
-    private final Command<S> command;
+    private final Command<S, ?> command;
     private final Map<String, ParsedArgument<S, ?>> arguments;
     private final CommandNode<S> rootNode;
     private final List<ParsedCommandNode<S>> nodes;
@@ -37,7 +37,7 @@ public class CommandContext<S> {
     private final RedirectModifier<S> modifier;
     private final boolean forks;
 
-    public CommandContext(final S source, final String input, final Map<String, ParsedArgument<S, ?>> arguments, final Command<S> command, final CommandNode<S> rootNode, final List<ParsedCommandNode<S>> nodes, final StringRange range, final CommandContext<S> child, final RedirectModifier<S> modifier, boolean forks) {
+    public CommandContext(final S source, final String input, final Map<String, ParsedArgument<S, ?>> arguments, final Command<S, ?> command, final CommandNode<S> rootNode, final List<ParsedCommandNode<S>> nodes, final StringRange range, final CommandContext<S> child, final RedirectModifier<S> modifier, boolean forks) {
         this.source = source;
         this.input = input;
         this.arguments = arguments;
@@ -69,7 +69,7 @@ public CommandContext<S> getLastChild() {
         return result;
     }
 
-    public Command<S> getCommand() {
+    public Command<S, ?> getCommand() {
         return command;
     }
 

src/main/java/com/mojang/brigadier/context/CommandContextBuilder.java

@@ -19,7 +19,7 @@ public class CommandContextBuilder<S> {
     private final List<ParsedCommandNode<S>> nodes = new ArrayList<>();
     private final CommandDispatcher<S> dispatcher;
     private S source;
-    private Command<S> command;
+    private Command<S, ?> command;
     private CommandContextBuilder<S> child;
     private StringRange range;
     private RedirectModifier<S> modifier = null;
@@ -54,7 +54,7 @@ public CommandContextBuilder<S> withArgument(final String name, final ParsedArgu
         return arguments;
     }
 
-    public CommandContextBuilder<S> withCommand(final Command<S> command) {
+    public CommandContextBuilder<S> withCommand(final Command<S, ?> command) {
         this.command = command;
         return this;
     }
@@ -95,7 +95,7 @@ public CommandContextBuilder<S> getLastChild() {
         return result;
     }
 
-    public Command<S> getCommand() {
+    public Command<S, ?> getCommand() {
         return command;
     }
 

src/main/java/com/mojang/brigadier/results/CommandResult.java

@@ -0,0 +1,39 @@
+// Copyright (c) Serena Lynas. All rights reserved.
+// Licensed under the MIT license.
+
+package com.mojang.brigadier.results;
+
+/**
+ * Optional interface for CommandResult
+ * 
+ * Not all things returned from commands
+ * must implement this interface.
+ */
+public interface CommandResult {
+    /**
+     * Combine one command result with another, returning
+     * the combined result.
+     * @param other The other result to combine this result
+     * with.
+     * @return The combined result
+     */
+    default Object combine(Object other) {
+        ListCommandResult list = new ListCommandResult();
+        list.combine(this);
+        list.combine(other);
+        return list;
+    }
+
+    static Object combine(Object target, Object source) {
+        if (target instanceof CommandResult) {
+            return ((CommandResult)target).combine(source);
+        } else if (target instanceof Integer && source instanceof Integer) {
+            // Backwards compatability
+            return (Integer)target + (Integer)source;
+        } else if (source instanceof EmptyCommandResult) {
+            return target;
+        } else {
+            return source;
+        }
+    }
+}

src/main/java/com/mojang/brigadier/results/EmptyCommandResult.java

@@ -0,0 +1,19 @@
+// Copyright (c) Serena Lynas. All rights reserved.
+// Licensed under the MIT license.
+
+package com.mojang.brigadier.results;
+
+/**
+ * Empty class which semantically represents
+ * an empty command result.
+ */
+public class EmptyCommandResult implements CommandResult {
+    /**
+     * Combines this result with another. Always overwrites
+     * the empty result.
+     */
+    @Override
+    public Object combine(Object other) {
+        return other;
+    }
+}

src/main/java/com/mojang/brigadier/results/ListCommandResult.java

@@ -0,0 +1,24 @@
+// Copyright (c) Serena Lynas. All rights reserved.
+// Licensed under the MIT license.
+
+package com.mojang.brigadier.results;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ListCommandResult implements CommandResult {
+    private List<Object> results = new ArrayList<>();
+
+    public List<Object> getResults() {
+        return results;
+    }
+
+    @Override
+    public ListCommandResult combine(Object other) {
+        if (!(other instanceof EmptyCommandResult)) {
+            results.add(other);
+        }
+
+        return this;
+    }
+}

src/main/java/com/mojang/brigadier/tree/ArgumentCommandNode.java

@@ -28,7 +28,7 @@ public class ArgumentCommandNode<S, T> extends CommandNode<S> {
     private final ArgumentType<T> type;
     private final SuggestionProvider<S> customSuggestions;
 
-    public ArgumentCommandNode(final String name, final ArgumentType<T> type, final Command<S> command, final Predicate<S> requirement, final CommandNode<S> redirect, final RedirectModifier<S> modifier, final boolean forks, final SuggestionProvider<S> customSuggestions) {
+    public ArgumentCommandNode(final String name, final ArgumentType<T> type, final Command<S, ?> command, final Predicate<S> requirement, final CommandNode<S> redirect, final RedirectModifier<S> modifier, final boolean forks, final SuggestionProvider<S> customSuggestions) {
         super(command, requirement, redirect, modifier, forks);
         this.name = name;
         this.type = type;

src/main/java/com/mojang/brigadier/tree/CommandNode.java

@@ -31,17 +31,17 @@ public abstract class CommandNode<S> implements Comparable<CommandNode<S>> {
     private final CommandNode<S> redirect;
     private final RedirectModifier<S> modifier;
     private final boolean forks;
-    private Command<S> command;
+    private Command<S, ?> command;
 
-    protected CommandNode(final Command<S> command, final Predicate<S> requirement, final CommandNode<S> redirect, final RedirectModifier<S> modifier, final boolean forks) {
+    protected CommandNode(final Command<S, ?> command, final Predicate<S> requirement, final CommandNode<S> redirect, final RedirectModifier<S> modifier, final boolean forks) {
         this.command = command;
         this.requirement = requirement;
         this.redirect = redirect;
         this.modifier = modifier;
         this.forks = forks;
     }
 
-    public Command<S> getCommand() {
+    public Command<S, ?> getCommand() {
         return command;
     }
 

src/main/java/com/mojang/brigadier/tree/LiteralCommandNode.java

@@ -24,7 +24,7 @@ public class LiteralCommandNode<S> extends CommandNode<S> {
     private final String literal;
     private final String literalLowerCase;
 
-    public LiteralCommandNode(final String literal, final Command<S> command, final Predicate<S> requirement, final CommandNode<S> redirect, final RedirectModifier<S> modifier, final boolean forks) {
+    public LiteralCommandNode(final String literal, final Command<S, ?> command, final Predicate<S> requirement, final CommandNode<S> redirect, final RedirectModifier<S> modifier, final boolean forks) {
         super(command, requirement, redirect, modifier, forks);
         this.literal = literal;
         this.literalLowerCase = literal.toLowerCase(Locale.ROOT);

src/test/java/com/mojang/brigadier/CommandDispatcherTest.java

@@ -36,7 +36,7 @@
 public class CommandDispatcherTest {
     private CommandDispatcher<Object> subject;
     @Mock
-    private Command<Object> command;
+    private Command<Object, Integer> command;
     @Mock
     private Object source;
 
@@ -167,7 +167,7 @@ public void testExecuteAmbiguousIncorrectArgument() throws Exception {
     @SuppressWarnings("unchecked")
     @Test
     public void testExecuteSubcommand() throws Exception {
-        final Command<Object> subCommand = mock(Command.class);
+        final Command<Object, Integer> subCommand = mock(Command.class);
         when(subCommand.run(any())).thenReturn(100);
 
         subject.register(literal("foo").then(
@@ -205,7 +205,7 @@ public void testParseIncompleteArgument() throws Exception {
     @SuppressWarnings("unchecked")
     @Test
     public void testExecuteAmbiguiousParentSubcommand() throws Exception {
-        final Command<Object> subCommand = mock(Command.class);
+        final Command<Object, Integer> subCommand = mock(Command.class);
         when(subCommand.run(any())).thenReturn(100);
 
         subject.register(
@@ -231,7 +231,7 @@ public void testExecuteAmbiguiousParentSubcommand() throws Exception {
     @SuppressWarnings("unchecked")
     @Test
     public void testExecuteAmbiguiousParentSubcommandViaRedirect() throws Exception {
-        final Command<Object> subCommand = mock(Command.class);
+        final Command<Object, Integer> subCommand = mock(Command.class);
         when(subCommand.run(any())).thenReturn(100);
 
         final LiteralCommandNode<Object> real = subject.register(
@@ -343,7 +343,7 @@ public void testExecuteOrphanedSubcommand() throws Exception {
 
     @Test
     public void testExecute_invalidOther() throws Exception {
-        final Command<Object> wrongCommand = mock(Command.class);
+        final Command<Object, Integer> wrongCommand = mock(Command.class);
         subject.register(literal("w").executes(wrongCommand));
         subject.register(literal("world").executes(command));
 

src/test/java/com/mojang/brigadier/CommandDispatcherUsagesTest.java

@@ -30,7 +30,7 @@ public class CommandDispatcherUsagesTest {
     @Mock
     private Object source;
     @Mock
-    private Command<Object> command;
+    private Command<Object, Integer> command;
 
     @Before
     public void setUp() throws Exception {

src/test/java/com/mojang/brigadier/builder/LiteralArgumentBuilderTest.java

@@ -19,7 +19,7 @@ public class LiteralArgumentBuilderTest {
     private LiteralArgumentBuilder<Object> builder;
     @Mock
     private
-    Command<Object> command;
+    Command<Object, Integer> command;
 
     @Before
     public void setUp() throws Exception {