Rename Permission to Precondition

src/Discord.Net.Commands/Attributes/PreconditionAttribute.cs

@@ -5,8 +5,8 @@ using System.Threading.Tasks;
 
 namespace Discord.Commands
 {
-    public abstract class PermissionAttribute : Attribute
+    public abstract class PreconditionAttribute : Attribute
     {
-        public abstract void CheckPermissions(PermissionsContext context);
+        public abstract void CheckPermissions(PreconditionContext context);
     }
 }

src/Discord.Net.Commands/Attributes/Preconditions/RequireDMAttribute.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Discord.Commands
+{
+    public class RequireDMAttribute : PreconditionAttribute
+    {
+        public override void CheckPermissions(PreconditionContext context)
+        {
+            if (context.Message.Channel is IGuildChannel)
+                context.Handled = true;
+        }
+    }
+}

src/Discord.Net.Commands/Attributes/Preconditions/RequireGuildAttribute.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Discord.Commands
+{
+    public class RequireGuildAttribute : PreconditionAttribute
+    {
+        public override void CheckPermissions(PreconditionContext context)
+        {
+            if (!(context.Message.Channel is IGuildChannel))
+                context.Handled = true;
+        }
+    }
+}

src/Discord.Net.Commands/Command.cs

@@ -19,7 +19,7 @@ namespace Discord.Commands
         public string Text { get; }
         public Module Module { get; }
         public IReadOnlyList<CommandParameter> Parameters { get; }
-        public IReadOnlyList<PermissionAttribute> Permissions { get; }
+        public IReadOnlyList<PreconditionAttribute> Permissions { get; }
 
         internal Command(Module module, object instance, CommandAttribute attribute, MethodInfo methodInfo, string groupPrefix)
         {
@@ -42,11 +42,11 @@ namespace Discord.Commands
             _action = BuildAction(methodInfo);
         }
 
-        public bool CanExecute(IMessage message)
+        public bool MeetsPreconditions(IMessage message)
         {
-            var context = new PermissionsContext(this, message);
+            var context = new PreconditionContext(this, message);
 
-            foreach (PermissionAttribute permission in Permissions)
+            foreach (PreconditionAttribute permission in Permissions)
             {
                 permission.CheckPermissions(context);
                 if (context.Handled)
@@ -68,8 +68,8 @@ namespace Discord.Commands
             if (!parseResult.IsSuccess)
                 return ExecuteResult.FromError(parseResult);
 
-            if (!CanExecute(msg)) // TODO: should we have to check this here, or leave it entirely to the bot dev?
-                return ExecuteResult.FromError(CommandError.InvalidPermissions, "Permissions check failed");
+            if (!MeetsPreconditions(msg)) // TODO: should we have to check this here, or leave it entirely to the bot dev?
+                return ExecuteResult.FromError(CommandError.UnmetPrecondition, "Permissions check failed");
 
             try
             {
@@ -82,9 +82,9 @@ namespace Discord.Commands
             }
         }
 
-        private IReadOnlyList<PermissionAttribute> BuildPermissions(MethodInfo methodInfo)
+        private IReadOnlyList<PreconditionAttribute> BuildPermissions(MethodInfo methodInfo)
         {
-            return methodInfo.GetCustomAttributes<PermissionAttribute>().ToImmutableArray();
+            return methodInfo.GetCustomAttributes<PreconditionAttribute>().ToImmutableArray();
         }
 
         private IReadOnlyList<CommandParameter> BuildParameters(MethodInfo methodInfo)

src/Discord.Net.Commands/CommandError.cs

@@ -16,6 +16,6 @@
 
         //Execute
         Exception,
-        InvalidPermissions
+        UnmetPrecondition
     }
 }

src/Discord.Net.Commands/CommandService.cs

@@ -211,10 +211,10 @@ namespace Discord.Commands
             // TODO: this logic is for users who don't manually search/execute: should we keep it?
             
             IReadOnlyList<Command> commands = searchResult.Commands
-                .Where(x => x.CanExecute(message)).ToImmutableArray();
+                .Where(x => x.MeetsPreconditions(message)).ToImmutableArray();
 
             if (commands.Count == 0 && searchResult.Commands.Count > 0)
-                return ParseResult.FromError(CommandError.InvalidPermissions, "Invalid permissions");
+                return ParseResult.FromError(CommandError.UnmetPrecondition, "Unmet precondition");
 
             for (int i = commands.Count - 1; i >= 0; i--)
             {

src/Discord.Net.Commands/Context/PreconditionContext.cs

@@ -5,16 +5,16 @@ using System.Threading.Tasks;
 
 namespace Discord.Commands
 {
-    public class PermissionsContext
+    public class PreconditionContext
     {
-        public Command ExecutingCommand { get; internal set; }
+        public Command Command { get; internal set; }
         public IMessage Message { get; internal set; }
 
         public bool Handled { get; set; }
 
-        internal PermissionsContext(Command command, IMessage message)
+        internal PreconditionContext(Command command, IMessage message)
         {
-            ExecutingCommand = command;
+            Command = command;
             Message = message;
 
             Handled = false;