core: Add @Liberal annotation to mark boolean arguments as liberal (#288)

cloud-core/src/main/java/cloud/commandframework/annotations/specifier/Liberal.java

@@ -0,0 +1,41 @@
+//
+// MIT License
+//
+// Copyright (c) 2021 Alexander Söderberg & Contributors
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+package cloud.commandframework.annotations.specifier;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation used to set the parsing mode of a {@link cloud.commandframework.arguments.standard.BooleanArgument boolean
+ * argument} to liberal.
+ *
+ * @since 1.6.0
+ */
+@Target(ElementType.PARAMETER)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Liberal {
+
+}

cloud-core/src/main/java/cloud/commandframework/arguments/parser/StandardParameters.java

@@ -65,6 +65,12 @@ public final class StandardParameters {
      * @since 1.5.0
      */
     public static final ParserParameter<Boolean> QUOTED = create("quoted", TypeToken.get(Boolean.class));
+    /**
+     * Indicates that a boolean argument should be liberal.
+     *
+     * @since 1.6.0
+     */
+    public static final ParserParameter<Boolean> LIBERAL = create("liberal", TypeToken.get(Boolean.class));
 
     private StandardParameters() {
     }

cloud-core/src/main/java/cloud/commandframework/arguments/parser/StandardParserRegistry.java

@@ -24,6 +24,7 @@
 package cloud.commandframework.arguments.parser;
 
 import cloud.commandframework.annotations.specifier.Greedy;
+import cloud.commandframework.annotations.specifier.Liberal;
 import cloud.commandframework.annotations.specifier.Quoted;
 import cloud.commandframework.annotations.specifier.Range;
 import cloud.commandframework.arguments.standard.BooleanArgument;
@@ -98,6 +99,10 @@ public final class StandardParserRegistry<C> implements ParserRegistry<C> {
                 Quoted.class,
                 (quoted, typeToken) -> ParserParameters.single(StandardParameters.QUOTED, true)
         );
+        this.<Liberal, Boolean>registerAnnotationMapper(
+                Liberal.class,
+                (liberal, typeToken) -> ParserParameters.single(StandardParameters.LIBERAL, true)
+        );
 
         /* Register standard types */
         this.registerParserSupplier(TypeToken.get(Byte.class), options ->
@@ -154,8 +159,10 @@ public final class StandardParserRegistry<C> implements ParserRegistry<C> {
                     (context, s) -> Arrays.asList(options.get(StandardParameters.COMPLETIONS, new String[0]))
             );
         });
-        /* Add options to this */
+        this.registerParserSupplier(TypeToken.get(Boolean.class), options -> {
-        this.registerParserSupplier(TypeToken.get(Boolean.class), options -> new BooleanArgument.BooleanParser<>(false));
+            final boolean liberal = options.get(StandardParameters.LIBERAL, false);
+            return new BooleanArgument.BooleanParser<>(liberal);
+        });
         this.registerParserSupplier(TypeToken.get(UUID.class), options -> new UUIDArgument.UUIDParser<>());
     }