Add helper method for flags to MutableCommandBuilder

cloud-kotlin-extensions/src/main/kotlin/cloud/commandframework/kotlin/MutableCommandBuilder.kt

@@ -475,4 +475,101 @@ public class MutableCommandBuilder<C : Any> {
         handler: CommandExecutionHandler<C>
     ): MutableCommandBuilder<C> =
         mutate { it.handler(handler) }
+
+    /**
+     * Add a new flag argument to this command
+     *
+     * @param name name of the flag
+     * @param aliases flag aliases
+     * @param description description of the flag
+     * @param argumentSupplier argument supplier for the flag
+     * @return this mutable builder
+     * @since 1.4.0
+     */
+    public fun flag(
+        name: String,
+        aliases: Array<String> = emptyArray(),
+        description: Description = Description.empty(),
+        argumentSupplier: () -> CommandArgument<C, *>
+    ): MutableCommandBuilder<C> = mutate {
+        it.flag(
+            this.commandManager.flagBuilder(name)
+                .withAliases(*aliases)
+                .withDescription(description)
+                .withArgument(argumentSupplier())
+                .build()
+        )
+    }
+
+    /**
+     * Add a new flag argument to this command
+     *
+     * @param name name of the flag
+     * @param aliases flag aliases
+     * @param description description of the flag
+     * @param argument argument for the flag
+     * @return this mutable builder
+     * @since 1.4.0
+     */
+    public fun flag(
+        name: String,
+        aliases: Array<String> = emptyArray(),
+        description: Description = Description.empty(),
+        argument: CommandArgument<C, *>
+    ): MutableCommandBuilder<C> = mutate {
+        it.flag(
+            this.commandManager.flagBuilder(name)
+                .withAliases(*aliases)
+                .withDescription(description)
+                .withArgument(argument)
+                .build()
+        )
+    }
+
+    /**
+     * Add a new flag argument to this command
+     *
+     * @param name name of the flag
+     * @param aliases flag aliases
+     * @param description description of the flag
+     * @param argumentBuilder command argument builder for the flag
+     * @return this mutable builder
+     * @since 1.4.0
+     */
+    public fun flag(
+        name: String,
+        aliases: Array<String> = emptyArray(),
+        description: Description = Description.empty(),
+        argumentBuilder: CommandArgument.Builder<C, *>
+    ): MutableCommandBuilder<C> = mutate {
+        it.flag(
+            this.commandManager.flagBuilder(name)
+                .withAliases(*aliases)
+                .withDescription(description)
+                .withArgument(argumentBuilder)
+                .build()
+        )
+    }
+
+    /**
+     * Add a new presence flag argument to this command
+     *
+     * @param name name of the flag
+     * @param aliases flag aliases
+     * @param description description of the flag
+     * @return this mutable builder
+     * @since 1.4.0
+     */
+    public fun flag(
+        name: String,
+        aliases: Array<String> = emptyArray(),
+        description: Description = Description.empty(),
+    ): MutableCommandBuilder<C> = mutate {
+        it.flag(
+            this.commandManager.flagBuilder(name)
+                .withAliases(*aliases)
+                .withDescription(description)
+                .build()
+        )
+    }
 }