Add command overload builders

This should make command builders a lot cleaner for lib users and
also makes #264 possible.

src/Discord.Net.Commands/Builders/CommandBuilder.cs

@@ -7,41 +7,35 @@ namespace Discord.Commands.Builders
 {
     public class CommandBuilder
     {
-        private readonly List<PreconditionAttribute> _preconditions;
-        private readonly List<ParameterBuilder> _parameters;
         private readonly List<string> _aliases;
+        private readonly List<OverloadBuilder> _overloads;
 
         public ModuleBuilder Module { get; }
-        internal Func<CommandContext, object[], IDependencyMap, Task> Callback { get; set; }
 
         public string Name { get; set; }
         public string Summary { get; set; }
         public string Remarks { get; set; }
-        public RunMode RunMode { get; set; }
-        public int Priority { get; set; }
 
-        public IReadOnlyList<PreconditionAttribute> Preconditions => _preconditions;
-        public IReadOnlyList<ParameterBuilder> Parameters => _parameters;
         public IReadOnlyList<string> Aliases => _aliases;
+        public IReadOnlyList<OverloadBuilder> Overloads => _overloads;
 
         //Automatic
         internal CommandBuilder(ModuleBuilder module)
         {
             Module = module;
 
-            _preconditions = new List<PreconditionAttribute>();
-            _parameters = new List<ParameterBuilder>();
             _aliases = new List<string>();
+            _overloads = new List<OverloadBuilder>();
         }
         //User-defined
-        internal CommandBuilder(ModuleBuilder module, string primaryAlias, Func<CommandContext, object[], IDependencyMap, Task> callback)
+        internal CommandBuilder(ModuleBuilder module, string primaryAlias, Action<OverloadBuilder> defaultOverloadBuilder)
             : this(module)
         {
-            Discord.Preconditions.NotNull(primaryAlias, nameof(primaryAlias));
-            Discord.Preconditions.NotNull(callback, nameof(callback));
-
-            Callback = callback;
+            Preconditions.NotNull(primaryAlias, nameof(primaryAlias));
+            Preconditions.NotNull(defaultOverloadBuilder, nameof(defaultOverloadBuilder));
+            
             _aliases.Add(primaryAlias);
+            AddOverload(defaultOverloadBuilder);
         }
 
         public CommandBuilder WithName(string name)
@@ -59,39 +53,17 @@ namespace Discord.Commands.Builders
             Remarks = remarks;
             return this;
         }
-        public CommandBuilder WithRunMode(RunMode runMode)
-        {
-            RunMode = runMode;
-            return this;
-        }
-        public CommandBuilder WithPriority(int priority)
-        {
-            Priority = priority;
-            return this;
-        }
 
         public CommandBuilder AddAliases(params string[] aliases)
         {
             _aliases.AddRange(aliases);
             return this;
         }
-        public CommandBuilder AddPrecondition(PreconditionAttribute precondition)
+        public CommandBuilder AddOverload(Action<OverloadBuilder> overloadBuilder)
         {
-            _preconditions.Add(precondition);
-            return this;
-        }
-        public CommandBuilder AddParameter(string name, Type type, Action<ParameterBuilder> createFunc)
-        {
-            var param = new ParameterBuilder(this, name, type);
-            createFunc(param);
-            _parameters.Add(param);
-            return this;
-        }
-        internal CommandBuilder AddParameter(Action<ParameterBuilder> createFunc)
-        {
-            var param = new ParameterBuilder(this);
-            createFunc(param);
-            _parameters.Add(param);
+            var overload = new OverloadBuilder(this);
+            overloadBuilder(overload);
+            _overloads.Add(overload);
             return this;
         }
 
@@ -101,19 +73,6 @@ namespace Discord.Commands.Builders
             if (Name == null)
                 Name = _aliases[0];
 
-            if (_parameters.Count > 0)
-            {
-                var lastParam = _parameters[_parameters.Count - 1];
-
-                var firstMultipleParam = _parameters.FirstOrDefault(x => x.IsMultiple);
-                if ((firstMultipleParam != null) && (firstMultipleParam != lastParam))
-                    throw new InvalidOperationException("Only the last parameter in a command may have the Multiple flag.");
-                
-                var firstRemainderParam = _parameters.FirstOrDefault(x => x.IsRemainder);
-                if ((firstRemainderParam != null) && (firstRemainderParam != lastParam))
-                    throw new InvalidOperationException("Only the last parameter in a command may have the Remainder flag.");
-            }
-
             return new CommandInfo(this, info, service);
         }
     }

src/Discord.Net.Commands/Builders/ModuleBuilder.cs

@@ -68,10 +68,10 @@ namespace Discord.Commands.Builders
             _preconditions.Add(precondition);
             return this;
         }
-        public ModuleBuilder AddCommand(string primaryAlias, Func<CommandContext, object[], IDependencyMap, Task> callback, Action<CommandBuilder> createFunc)
+        public ModuleBuilder AddCommand(string primaryAlias, Action<OverloadBuilder> defaultOverloadBuilder, Action<CommandBuilder> createFunc = null)
         {
-            var builder = new CommandBuilder(this, primaryAlias, callback);
-            createFunc(builder);
+            var builder = new CommandBuilder(this, primaryAlias, defaultOverloadBuilder);
+            createFunc?.Invoke(builder);
             _commands.Add(builder);
             return this;
         }

src/Discord.Net.Commands/Builders/ModuleClassBuilder.cs

@@ -104,15 +104,28 @@ namespace Discord.Commands
 
             var validCommands = typeInfo.DeclaredMethods.Where(x => IsValidCommandDefinition(x));
 
-            foreach (var method in validCommands)
+            var groupedCommands = validCommands.GroupBy(x => x.GetCustomAttribute<CommandAttribute>().Text);
+
+            foreach (var overloads in groupedCommands)
             {
-                builder.AddCommand((command) => {
-                    BuildCommand(command, typeInfo, method, service);
+                builder.AddCommand((command) =>
+                {
+                    foreach (var method in overloads)
+                    {
+                        command.AddOverload((overload) =>
+                        {
+                            BuildOverload(overload, typeInfo, method, service);
+                        });
+                    }
+
+                    var defaultOverload = overloads.OrderByDescending(x => x.GetCustomAttribute<PriorityAttribute>()?.Priority ?? 0).First();
+
+                    BuildCommand(command, defaultOverload, service);
                 });
             }
         }
 
-        private static void BuildCommand(CommandBuilder builder, TypeInfo typeInfo, MethodInfo method, CommandService service)
+        private static void BuildCommand(CommandBuilder builder, MethodInfo method, CommandService service)
         {
             var attributes = method.GetCustomAttributes();
             
@@ -123,25 +136,36 @@ namespace Discord.Commands
                 {
                     var cmdAttr = attribute as CommandAttribute;
                     builder.AddAliases(cmdAttr.Text);
-                    builder.RunMode = cmdAttr.RunMode;
                     builder.Name = builder.Name ?? cmdAttr.Text;
                 }
                 else if (attribute is NameAttribute)
                     builder.Name = (attribute as NameAttribute).Text;
-                else if (attribute is PriorityAttribute)
-                    builder.Priority = (attribute as PriorityAttribute).Priority;
                 else if (attribute is SummaryAttribute)
                     builder.Summary = (attribute as SummaryAttribute).Text;
                 else if (attribute is RemarksAttribute)
                     builder.Remarks = (attribute as RemarksAttribute).Text;
                 else if (attribute is AliasAttribute)
                     builder.AddAliases((attribute as AliasAttribute).Aliases);
-                else if (attribute is PreconditionAttribute)
-                    builder.AddPrecondition(attribute as PreconditionAttribute);
             }
 
             if (builder.Name == null)
                 builder.Name = method.Name;
+        }
+
+        private static void BuildOverload(OverloadBuilder builder, TypeInfo typeInfo, MethodInfo method, CommandService service)
+        {
+            var attributes = method.GetCustomAttributes();
+
+            foreach (var attribute in attributes)
+            {
+                // TODO: C#7 type switch
+                if (attribute is CommandAttribute)
+                    builder.RunMode = (attribute as CommandAttribute).RunMode;
+                else if (attribute is PriorityAttribute)
+                    builder.Priority = (attribute as PriorityAttribute).Priority;
+                else if (attribute is PreconditionAttribute)
+                    builder.AddPrecondition(attribute as PreconditionAttribute);
+            }
 
             var parameters = method.GetParameters();
             int pos = 0, count = parameters.Length;
@@ -161,7 +185,8 @@ namespace Discord.Commands
                 {
                     return method.Invoke(instance, args) as Task ?? Task.CompletedTask;
                 }
-                finally{
+                finally
+                {
                     (instance as IDisposable)?.Dispose();
                 }
             };

src/Discord.Net.Commands/Builders/OverloadBuilder.cs

@@ -0,0 +1,83 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Collections.Generic;
+using System.Diagnostics;
+
+namespace Discord.Commands.Builders
+{
+    public class OverloadBuilder
+    {
+        private readonly List<PreconditionAttribute> _preconditions;
+        private readonly List<ParameterBuilder> _parameters;
+
+        public CommandBuilder Command { get; }
+        internal Func<CommandContext, object[], IDependencyMap, Task> Callback { get; set; }
+
+        public RunMode RunMode { get; set; }
+        public int Priority { get; set; }
+
+        public IReadOnlyList<PreconditionAttribute> Preconditions => _preconditions;
+        public IReadOnlyList<ParameterBuilder> Parameters => _parameters;
+
+        internal OverloadBuilder(CommandBuilder command)
+        {
+            Command = command;
+
+            _preconditions = new List<PreconditionAttribute>();
+            _parameters = new List<ParameterBuilder>();
+        }
+
+        public OverloadBuilder WithRunMode(RunMode runMode)
+        {
+            RunMode = runMode;
+            return this;
+        }
+
+        public OverloadBuilder WithPriority(int priority)
+        {
+            Priority = priority;
+            return this;
+        }
+
+        public OverloadBuilder AddPrecondition(PreconditionAttribute precondition)
+        {
+            _preconditions.Add(precondition);
+            return this;
+        }
+        internal OverloadBuilder AddParameter(Action<ParameterBuilder> createFunc)
+        {
+            var param = new ParameterBuilder(Command);
+            createFunc(param);
+            _parameters.Add(param);
+            return this;
+        }
+        public OverloadBuilder AddParameter(string name, Type type, Action<ParameterBuilder> createFunc)
+        {
+            var param = new ParameterBuilder(Command, name, type);
+            createFunc(param);
+            _parameters.Add(param);
+            return this;
+        }
+
+        internal OverloadInfo Build(CommandInfo info, CommandService service)
+        {
+            Discord.Preconditions.NotNull(Callback, nameof(Callback));
+
+            if (_parameters.Count > 0)
+            {
+                var lastParam = _parameters[_parameters.Count - 1];
+
+                var firstMultipleParam = _parameters.FirstOrDefault(x => x.IsMultiple);
+                if ((firstMultipleParam != null) && (firstMultipleParam != lastParam))
+                    throw new InvalidOperationException("Only the last parameter in a command may have the Multiple flag.");
+
+                var firstRemainderParam = _parameters.FirstOrDefault(x => x.IsRemainder);
+                if ((firstRemainderParam != null) && (firstRemainderParam != lastParam))
+                    throw new InvalidOperationException("Only the last parameter in a command may have the Remainder flag.");
+            }
+
+            return new OverloadInfo(this, info, service);
+        }
+    }
+}

src/Discord.Net.Commands/Builders/ParameterBuilder.cs

@@ -87,7 +87,7 @@ namespace Discord.Commands.Builders
             return this;
         }
 
-        internal ParameterInfo Build(CommandInfo info)
+        internal ParameterInfo Build(OverloadInfo info)
         {
             if (TypeReader == null)
                 throw new InvalidOperationException($"No default TypeReader found, one must be specified");
@@ -95,4 +95,4 @@ namespace Discord.Commands.Builders
             return new ParameterInfo(this, info, Command.Module.Service);
         }
     }
-}
+}

src/Discord.Net.Commands/CommandParser.cs

@@ -13,7 +13,7 @@ namespace Discord.Commands
             QuotedParameter
         }
         
-        public static async Task<ParseResult> ParseArgs(CommandInfo command, CommandContext context, string input, int startPos)
+        public static async Task<ParseResult> ParseArgs(OverloadInfo overload, CommandContext context, string input, int startPos)
         {
             ParameterInfo curParam = null;
             StringBuilder argBuilder = new StringBuilder(input.Length);
@@ -66,7 +66,7 @@ namespace Discord.Commands
                     else
                     {
                         if (curParam == null)
-                            curParam = command.Parameters.Count > argList.Count ? command.Parameters[argList.Count] : null;
+                            curParam = overload.Parameters.Count > argList.Count ? overload.Parameters[argList.Count] : null;
 
                         if (curParam != null && curParam.IsRemainder)
                         {
@@ -145,9 +145,9 @@ namespace Discord.Commands
                 return ParseResult.FromError(CommandError.ParseFailed, "A quoted parameter is incomplete");
             
             //Add missing optionals
-            for (int i = argList.Count; i < command.Parameters.Count; i++)
+            for (int i = argList.Count; i < overload.Parameters.Count; i++)
             {
-                var param = command.Parameters[i];
+                var param = overload.Parameters[i];
                 if (param.IsMultiple)
                     continue;
                 if (!param.IsOptional)
@@ -155,7 +155,7 @@ namespace Discord.Commands
                 argList.Add(TypeReaderResult.FromSuccess(param.DefaultValue));
             }
             
-            return ParseResult.FromSuccess(argList.ToImmutable(), paramList.ToImmutable());
+            return ParseResult.FromSuccess(overload, argList.ToImmutable(), paramList.ToImmutable());
         }
     }
 }

src/Discord.Net.Commands/CommandService.cs

@@ -39,8 +39,8 @@ namespace Discord.Commands
             _defaultTypeReaders = new ConcurrentDictionary<Type, TypeReader>
             {
                 [typeof(bool)] = new SimpleTypeReader<bool>(),
-                [typeof(char)] = new SimpleTypeReader<char>(),
-                [typeof(string)] = new SimpleTypeReader<string>(),
+                [typeof(char)] = new SimpleTypeReader<char>(0),
+                [typeof(string)] = new SimpleTypeReader<string>(0),
                 [typeof(byte)] = new SimpleTypeReader<byte>(),
                 [typeof(sbyte)] = new SimpleTypeReader<sbyte>(),
                 [typeof(ushort)] = new SimpleTypeReader<ushort>(),
@@ -228,8 +228,8 @@ namespace Discord.Commands
         public SearchResult Search(CommandContext context, string input)
         {
             string searchInput = _caseSensitive ? input : input.ToLowerInvariant();
-            var matches = _map.GetCommands(searchInput).OrderByDescending(x => x.Priority).ToImmutableArray();
-            
+            var matches = _map.GetCommands(input).OrderBy(x => x.Overloads.Average(y => y.Priority)).ToImmutableArray();
+
             if (matches.Length > 0)
                 return SearchResult.FromSuccess(input, matches);
             else
@@ -249,41 +249,67 @@ namespace Discord.Commands
             var commands = searchResult.Commands;
             for (int i = commands.Count - 1; i >= 0; i--)
             {
-                var preconditionResult = await commands[i].CheckPreconditionsAsync(context, dependencyMap).ConfigureAwait(false);
-                if (!preconditionResult.IsSuccess)
+                var command = commands[i];
+                var overloads = command.Overloads.OrderBy(x => x.Priority).ToImmutableArray();
+
+                PreconditionResult preconditionResult = PreconditionResult.FromSuccess();
+                for (int j = command.Overloads.Count - 1; i >= 0; i--)
+                {
+                    preconditionResult = await overloads[j].CheckPreconditionsAsync(context, dependencyMap).ConfigureAwait(false);
+                    if (!preconditionResult.IsSuccess)
+                    {
+                        if (commands.Count == 1)
+                            return preconditionResult;
+                        else
+                            continue;
+                    }
+                }
+
+                var rawParseResults = new List<ParseResult>();
+                foreach (var overload in overloads)
                 {
-                    if (commands.Count == 1)
-                        return preconditionResult;
-                    else
-                        continue;
+                    rawParseResults.Add(await overload.ParseAsync(context, searchResult, preconditionResult).ConfigureAwait(false));
                 }
 
-                var parseResult = await commands[i].ParseAsync(context, searchResult, preconditionResult).ConfigureAwait(false);
-                if (!parseResult.IsSuccess)
+                //order by average score
+                var orderedParseResults = rawParseResults.OrderBy(
+                    x => !x.IsSuccess ? 0 :
+                         (  x.ArgValues.Count > 0 ?   x.ArgValues.Average(y => y.Values.Max(z => z.Score)) : 0) +
+                         (x.ParamValues.Count > 0 ? x.ParamValues.Average(y => y.Values.Max(z => z.Score)) : 0));
+
+                var parseResults = orderedParseResults.ToImmutableArray();
+
+                for (int j = parseResults.Length - 1; j >= 0; j--)
                 {
-                    if (parseResult.Error == CommandError.MultipleMatches)
+                    var parseResult = parseResults[j];
+                    var overload = parseResult.Overload;
+
+                    if (!parseResult.IsSuccess)
                     {
-                        IReadOnlyList<TypeReaderValue> argList, paramList;
-                        switch (multiMatchHandling)
+                        if (parseResult.Error == CommandError.MultipleMatches)
                         {
-                            case MultiMatchHandling.Best:
-                                argList = parseResult.ArgValues.Select(x => x.Values.OrderByDescending(y => y.Score).First()).ToImmutableArray();
-                                paramList = parseResult.ParamValues.Select(x => x.Values.OrderByDescending(y => y.Score).First()).ToImmutableArray();
-                                parseResult = ParseResult.FromSuccess(argList, paramList);
-                                break;
+                            IReadOnlyList<TypeReaderValue> argList, paramList;
+                            switch (multiMatchHandling)
+                            {
+                                case MultiMatchHandling.Best:
+                                    argList = parseResult.ArgValues.Select(x => x.Values.OrderByDescending(y => y.Score).First()).ToImmutableArray();
+                                    paramList = parseResult.ParamValues.Select(x => x.Values.OrderByDescending(y => y.Score).First()).ToImmutableArray();
+                                    parseResult = ParseResult.FromSuccess(parseResult.Overload, argList, paramList);
+                                    break;
+                            }
                         }
-                    }
 
-                    if (!parseResult.IsSuccess)
-                    {
-                        if (commands.Count == 1)
-                            return parseResult;
-                        else
-                            continue;
+                        if (!parseResult.IsSuccess)
+                        {
+                            if (overloads.Length == 1)
+                                return parseResult;
+                            else
+                                continue;
+                        }
                     }
-                }
 
-                return await commands[i].Execute(context, parseResult, dependencyMap).ConfigureAwait(false);
+                    return await overload.Execute(context, parseResult, dependencyMap).ConfigureAwait(false);
+                }
             }
 
             return SearchResult.FromError(CommandError.UnknownCommand, "This input does not match any overload.");

src/Discord.Net.Commands/Info/CommandInfo.cs

@@ -5,43 +5,31 @@ using System.Collections.Immutable;
 using System.Collections.Concurrent;
 using System.Threading.Tasks;
 using System.Reflection;
+using System.Diagnostics;
 
 using Discord.Commands.Builders;
-using System.Diagnostics;
 
 namespace Discord.Commands
 {
     [DebuggerDisplay("{Name,nq}")]
     public class CommandInfo
     {
-        private static readonly System.Reflection.MethodInfo _convertParamsMethod = typeof(CommandInfo).GetTypeInfo().GetDeclaredMethod(nameof(ConvertParamsList));
-        private static readonly ConcurrentDictionary<Type, Func<IEnumerable<object>, object>> _arrayConverters = new ConcurrentDictionary<Type, Func<IEnumerable<object>, object>>();
-
-        private readonly Func<CommandContext, object[], IDependencyMap, Task> _action;
-
         public ModuleInfo Module { get; }
         public string Name { get; }
         public string Summary { get; }
         public string Remarks { get; }
-        public int Priority { get; }
-        public bool HasVarArgs { get; }
-        public RunMode RunMode { get; }
 
         public IReadOnlyList<string> Aliases { get; }
-        public IReadOnlyList<ParameterInfo> Parameters { get; }
-        public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
+        public IReadOnlyList<OverloadInfo> Overloads { get; }
 
         internal CommandInfo(CommandBuilder builder, ModuleInfo module, CommandService service)
         {
             Module = module;
-            
+
             Name = builder.Name;
             Summary = builder.Summary;
             Remarks = builder.Remarks;
 
-            RunMode = (builder.RunMode == RunMode.Default ? service._defaultRunMode : builder.RunMode);
-            Priority = builder.Priority;
-
             // both command and module provide aliases
             if (module.Aliases.Count > 0 && builder.Aliases.Count > 0)
                 Aliases = module.Aliases.Permutate(builder.Aliases, (first, second) => second != null ? first + " " + second : first).Select(x => service._caseSensitive ? x : x.ToLowerInvariant()).ToImmutableArray();
@@ -55,148 +43,7 @@ namespace Discord.Commands
             else
                 throw new InvalidOperationException("Cannot build a command without any aliases");
 
-            Preconditions = builder.Preconditions.ToImmutableArray();
-
-            Parameters = builder.Parameters.Select(x => x.Build(this)).ToImmutableArray();
-            HasVarArgs = builder.Parameters.Count > 0 ? builder.Parameters[builder.Parameters.Count - 1].IsMultiple : false;
-
-            _action = builder.Callback;
-        }
-
-        public async Task<PreconditionResult> CheckPreconditionsAsync(CommandContext context, IDependencyMap map = null)
-        {
-            if (map == null)
-                map = DependencyMap.Empty;
-
-            foreach (PreconditionAttribute precondition in Module.Preconditions)
-            {
-                var result = await precondition.CheckPermissions(context, this, map).ConfigureAwait(false);
-                if (!result.IsSuccess)
-                    return result;
-            }
-
-            foreach (PreconditionAttribute precondition in Preconditions)
-            {
-                var result = await precondition.CheckPermissions(context, this, map).ConfigureAwait(false);
-                if (!result.IsSuccess)
-                    return result;
-            }
-
-            return PreconditionResult.FromSuccess();
-        }
-
-        public async Task<ParseResult> ParseAsync(CommandContext context, SearchResult searchResult, PreconditionResult? preconditionResult = null)
-        {
-            if (!searchResult.IsSuccess)
-                return ParseResult.FromError(searchResult);
-            if (preconditionResult != null && !preconditionResult.Value.IsSuccess)
-                return ParseResult.FromError(preconditionResult.Value);
-            
-            string input = searchResult.Text;
-            var matchingAliases = Aliases.Where(alias => input.StartsWith(alias));
-            
-            string matchingAlias = "";
-            foreach (string alias in matchingAliases)
-            {
-                if (alias.Length > matchingAlias.Length)
-                    matchingAlias = alias;
-            }
-            
-            input = input.Substring(matchingAlias.Length);
-
-            return await CommandParser.ParseArgs(this, context, input, 0).ConfigureAwait(false);
+            Overloads = builder.Overloads.Select(x => x.Build(this, service)).ToImmutableArray();
         }
-
-        public Task<ExecuteResult> Execute(CommandContext context, ParseResult parseResult, IDependencyMap map)
-        {
-            if (!parseResult.IsSuccess)
-                return Task.FromResult(ExecuteResult.FromError(parseResult));
-
-            var argList = new object[parseResult.ArgValues.Count];
-            for (int i = 0; i < parseResult.ArgValues.Count; i++)
-            {
-                if (!parseResult.ArgValues[i].IsSuccess)
-                    return Task.FromResult(ExecuteResult.FromError(parseResult.ArgValues[i]));
-                argList[i] = parseResult.ArgValues[i].Values.First().Value;
-            }
-            
-            var paramList = new object[parseResult.ParamValues.Count];
-            for (int i = 0; i < parseResult.ParamValues.Count; i++)
-            {
-                if (!parseResult.ParamValues[i].IsSuccess)
-                    return Task.FromResult(ExecuteResult.FromError(parseResult.ParamValues[i]));
-                paramList[i] = parseResult.ParamValues[i].Values.First().Value;
-            }
-
-            return ExecuteAsync(context, argList, paramList, map);
-        }
-        public async Task<ExecuteResult> ExecuteAsync(CommandContext context, IEnumerable<object> argList, IEnumerable<object> paramList, IDependencyMap map)
-        {
-            if (map == null)
-                map = DependencyMap.Empty;
-
-            try
-            {
-                object[] args = GenerateArgs(argList, paramList);
-
-                foreach (var parameter in Parameters)
-                {
-                    var result = await parameter.CheckPreconditionsAsync(context, args, map).ConfigureAwait(false);
-                    if (!result.IsSuccess)
-                        return ExecuteResult.FromError(result);
-                }
-
-                switch (RunMode)
-                {
-                    case RunMode.Sync: //Always sync
-                        await _action(context, args, map).ConfigureAwait(false);
-                        break;
-                    case RunMode.Mixed: //Sync until first await statement
-                        var t1 = _action(context, args, map);
-                        break;
-                    case RunMode.Async: //Always async
-                        var t2 = Task.Run(() => _action(context, args, map));
-                        break;
-                }
-                return ExecuteResult.FromSuccess();
-            }
-            catch (Exception ex)
-            {
-                return ExecuteResult.FromError(ex);
-            }
-        }
-
-        private object[] GenerateArgs(IEnumerable<object> argList, IEnumerable<object> paramsList)
-        {
-            int argCount = Parameters.Count;
-            var array = new object[Parameters.Count];
-            if (HasVarArgs)
-                argCount--;
-
-            int i = 0;
-            foreach (var arg in argList)
-            {
-                if (i == argCount)
-                    throw new InvalidOperationException("Command was invoked with too many parameters");
-                array[i++] = arg;
-            }
-            if (i < argCount)
-                throw new InvalidOperationException("Command was invoked with too few parameters");
-
-            if (HasVarArgs)
-            {
-                var func = _arrayConverters.GetOrAdd(Parameters[Parameters.Count - 1].Type, t =>
-                {
-                    var method = _convertParamsMethod.MakeGenericMethod(t);
-                    return (Func<IEnumerable<object>, object>)method.CreateDelegate(typeof(Func<IEnumerable<object>, object>));
-                });
-                array[i] = func(paramsList);
-            }
-
-            return array;
-        }
-
-        private static T[] ConvertParamsList<T>(IEnumerable<object> paramsList)
-            => paramsList.Cast<T>().ToArray();
     }
-}
+}

src/Discord.Net.Commands/Info/OverloadInfo.cs

@@ -0,0 +1,175 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Collections.Concurrent;
+using System.Threading.Tasks;
+using System.Reflection;
+using System.Diagnostics;
+
+using Discord.Commands.Builders;
+
+namespace Discord.Commands
+{
+    [DebuggerDisplay("{DebuggerDisplay,nq}")]
+    public class OverloadInfo
+    {
+        private static readonly MethodInfo _convertParamsMethod = typeof(CommandInfo).GetTypeInfo().GetDeclaredMethod(nameof(ConvertParamsList));
+        private static readonly ConcurrentDictionary<Type, Func<IEnumerable<object>, object>> _arrayConverters = new ConcurrentDictionary<Type, Func<IEnumerable<object>, object>>();
+
+        private readonly Func<CommandContext, object[], IDependencyMap, Task> _action;
+
+        public CommandInfo Command { get; }
+        public int Priority { get; }
+        public bool HasVarArgs { get; }
+        public RunMode RunMode { get; }
+
+        public IReadOnlyList<ParameterInfo> Parameters { get; }
+        public IReadOnlyList<PreconditionAttribute> Preconditions { get; }
+
+        internal OverloadInfo(OverloadBuilder builder, CommandInfo command, CommandService service)
+        {
+            Command = command;
+
+            RunMode = (builder.RunMode == RunMode.Default ? service._defaultRunMode : builder.RunMode);
+            Priority = builder.Priority;
+
+            Preconditions = builder.Preconditions.ToImmutableArray();
+
+            Parameters = builder.Parameters.Select(x => x.Build(this)).ToImmutableArray();
+            HasVarArgs = builder.Parameters.Count > 0 ? builder.Parameters[builder.Parameters.Count - 1].IsMultiple : false;
+
+            _action = builder.Callback;
+        }
+
+        public async Task<PreconditionResult> CheckPreconditionsAsync(CommandContext context, IDependencyMap map = null)
+        {
+            if (map == null)
+                map = DependencyMap.Empty;
+
+            foreach (PreconditionAttribute precondition in Command.Module.Preconditions)
+            {
+                var result = await precondition.CheckPermissions(context, Command, map).ConfigureAwait(false);
+                if (!result.IsSuccess)
+                    return result;
+            }
+
+            foreach (PreconditionAttribute precondition in Preconditions)
+            {
+                var result = await precondition.CheckPermissions(context, Command, map).ConfigureAwait(false);
+                if (!result.IsSuccess)
+                    return result;
+            }
+
+            return PreconditionResult.FromSuccess();
+        }
+
+        public async Task<ParseResult> ParseAsync(CommandContext context, SearchResult searchResult, PreconditionResult? preconditionResult = null)
+        {
+            if (!searchResult.IsSuccess)
+                return ParseResult.FromError(searchResult);
+            if (preconditionResult != null && !preconditionResult.Value.IsSuccess)
+                return ParseResult.FromError(preconditionResult.Value);
+
+            string input = searchResult.Text;
+            var matchingAliases = Command.Aliases.Where(alias => input.StartsWith(alias));
+
+            string matchingAlias = "";
+            foreach (string alias in matchingAliases)
+            {
+                if (alias.Length > matchingAlias.Length)
+                    matchingAlias = alias;
+            }
+
+            input = input.Substring(matchingAlias.Length);
+
+            return await CommandParser.ParseArgs(this, context, input, 0).ConfigureAwait(false);
+        }
+
+        public Task<ExecuteResult> Execute(CommandContext context, ParseResult parseResult, IDependencyMap map)
+        {
+            if (!parseResult.IsSuccess)
+                return Task.FromResult(ExecuteResult.FromError(parseResult));
+
+            var argList = new object[parseResult.ArgValues.Count];
+            for (int i = 0; i < parseResult.ArgValues.Count; i++)
+            {
+                if (!parseResult.ArgValues[i].IsSuccess)
+                    return Task.FromResult(ExecuteResult.FromError(parseResult.ArgValues[i]));
+                argList[i] = parseResult.ArgValues[i].Values.First().Value;
+            }
+
+            var paramList = new object[parseResult.ParamValues.Count];
+            for (int i = 0; i < parseResult.ParamValues.Count; i++)
+            {
+                if (!parseResult.ParamValues[i].IsSuccess)
+                    return Task.FromResult(ExecuteResult.FromError(parseResult.ParamValues[i]));
+                paramList[i] = parseResult.ParamValues[i].Values.First().Value;
+            }
+
+            return ExecuteAsync(context, argList, paramList, map);
+        }
+        public async Task<ExecuteResult> ExecuteAsync(CommandContext context, IEnumerable<object> argList, IEnumerable<object> paramList, IDependencyMap map)
+        {
+            if (map == null)
+                map = DependencyMap.Empty;
+
+            try
+            {
+                var args = GenerateArgs(argList, paramList);
+                switch (RunMode)
+                {
+                    case RunMode.Sync: //Always sync
+                        await _action(context, args, map).ConfigureAwait(false);
+                        break;
+                    case RunMode.Mixed: //Sync until first await statement
+                        var t1 = _action(context, args, map);
+                        break;
+                    case RunMode.Async: //Always async
+                        var t2 = Task.Run(() => _action(context, args, map));
+                        break;
+                }
+                return ExecuteResult.FromSuccess();
+            }
+            catch (Exception ex)
+            {
+                return ExecuteResult.FromError(ex);
+            }
+        }
+
+        private object[] GenerateArgs(IEnumerable<object> argList, IEnumerable<object> paramsList)
+        {
+            int argCount = Parameters.Count;
+            var array = new object[Parameters.Count];
+            if (HasVarArgs)
+                argCount--;
+
+            int i = 0;
+            foreach (var arg in argList)
+            {
+                if (i == argCount)
+                    throw new InvalidOperationException("Command was invoked with too many parameters");
+                array[i++] = arg;
+            }
+            if (i < argCount)
+                throw new InvalidOperationException("Command was invoked with too few parameters");
+
+            if (HasVarArgs)
+            {
+                var func = _arrayConverters.GetOrAdd(Parameters[Parameters.Count - 1].Type, t =>
+                {
+                    var method = _convertParamsMethod.MakeGenericMethod(t);
+                    return (Func<IEnumerable<object>, object>)method.CreateDelegate(typeof(Func<IEnumerable<object>, object>));
+                });
+                array[i] = func(paramsList);
+            }
+
+            return array;
+        }
+
+        private string DebuggerDisplay => $"{Command.Name} ({Priority}, {RunMode})";
+
+        private static T[] ConvertParamsList<T>(IEnumerable<object> paramsList)
+            => paramsList.Cast<T>().ToArray();
+    }
+}

src/Discord.Net.Commands/Info/ParameterInfo.cs

@@ -3,16 +3,19 @@ using System.Linq;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading.Tasks;
+using System.Diagnostics;
 
 using Discord.Commands.Builders;
 
 namespace Discord.Commands
 {
+    [DebuggerDisplay("{DebuggerDisplay,nq}")]
     public class ParameterInfo
     {
         private readonly TypeReader _reader;
+        private readonly OverloadInfo _overload;
 
-        public CommandInfo Command { get; }
+        public CommandInfo Command => _overload.Command;
         public string Name { get; }
         public string Summary { get; }
         public bool IsOptional { get; }
@@ -23,9 +26,9 @@ namespace Discord.Commands
 
         public IReadOnlyList<ParameterPreconditionAttribute> Preconditions { get; }
 
-        internal ParameterInfo(ParameterBuilder builder, CommandInfo command, CommandService service)
+        internal ParameterInfo(ParameterBuilder builder, OverloadInfo overload, CommandService service)
         {
-            Command = command;
+            _overload = overload;
 
             Name = builder.Name;
             Summary = builder.Summary;
@@ -69,4 +72,4 @@ namespace Discord.Commands
         public override string ToString() => Name;
         private string DebuggerDisplay => $"{Name}{(IsOptional ? " (Optional)" : "")}{(IsRemainder ? " (Remainder)" : "")}";
     }
-}
+}

src/Discord.Net.Commands/Readers/SimpleTypeReader.cs

@@ -6,16 +6,19 @@ namespace Discord.Commands
     {
         private readonly TryParseDelegate<T> _tryParse;
 
-        public SimpleTypeReader()
+        private readonly float _score;
+
+        public SimpleTypeReader(float score = 1)
         {
             _tryParse = PrimitiveParsers.Get<T>();
+            _score = score;
         }
 
         public override Task<TypeReaderResult> Read(CommandContext context, string input)
         {
             T value;
             if (_tryParse(input, out value))
-                return Task.FromResult(TypeReaderResult.FromSuccess(value));
+                return Task.FromResult(TypeReaderResult.FromSuccess(new TypeReaderValue(value, _score)));
             return Task.FromResult(TypeReaderResult.FromError(CommandError.ParseFailed, $"Failed to parse {typeof(T).Name}"));
         }
     }

src/Discord.Net.Commands/Results/ParseResult.cs

@@ -9,34 +9,37 @@ namespace Discord.Commands
         public IReadOnlyList<TypeReaderResult> ArgValues { get; }
         public IReadOnlyList<TypeReaderResult> ParamValues { get; }
 
+        public OverloadInfo Overload { get; }
+
         public CommandError? Error { get; }
         public string ErrorReason { get; }
 
         public bool IsSuccess => !Error.HasValue;
 
-        private ParseResult(IReadOnlyList<TypeReaderResult> argValues, IReadOnlyList<TypeReaderResult> paramValue, CommandError? error, string errorReason)
+        private ParseResult(OverloadInfo overload, IReadOnlyList<TypeReaderResult> argValues, IReadOnlyList<TypeReaderResult> paramValue, CommandError? error, string errorReason)
         {
+            Overload = overload;
             ArgValues = argValues;
             ParamValues = paramValue;
             Error = error;
             ErrorReason = errorReason;
         }
 
-        public static ParseResult FromSuccess(IReadOnlyList<TypeReaderResult> argValues, IReadOnlyList<TypeReaderResult> paramValues)
+        public static ParseResult FromSuccess(OverloadInfo overload, IReadOnlyList<TypeReaderResult> argValues, IReadOnlyList<TypeReaderResult> paramValues)
         {
             for (int i = 0; i < argValues.Count; i++)
             {
                 if (argValues[i].Values.Count > 1)
-                    return new ParseResult(argValues, paramValues, CommandError.MultipleMatches, "Multiple matches found.");
+                    return new ParseResult(overload, argValues, paramValues, CommandError.MultipleMatches, "Multiple matches found.");
             }
             for (int i = 0; i < paramValues.Count; i++)
             {
                 if (paramValues[i].Values.Count > 1)
-                    return new ParseResult(argValues, paramValues, CommandError.MultipleMatches, "Multiple matches found.");
+                    return new ParseResult(overload, argValues, paramValues, CommandError.MultipleMatches, "Multiple matches found.");
             }
-            return new ParseResult(argValues, paramValues, null, null);
+            return new ParseResult(overload, argValues, paramValues, null, null);
         }
-        public static ParseResult FromSuccess(IReadOnlyList<TypeReaderValue> argValues, IReadOnlyList<TypeReaderValue> paramValues)
+        public static ParseResult FromSuccess(OverloadInfo overload, IReadOnlyList<TypeReaderValue> argValues, IReadOnlyList<TypeReaderValue> paramValues)
         {
             var argList = new TypeReaderResult[argValues.Count];
             for (int i = 0; i < argValues.Count; i++)
@@ -48,13 +51,13 @@ namespace Discord.Commands
                 for (int i = 0; i < paramValues.Count; i++)
                     paramList[i] = TypeReaderResult.FromSuccess(paramValues[i]);
             }
-            return new ParseResult(argList, paramList, null, null);
+            return new ParseResult(overload, argList, paramList, null, null);
         }
 
         public static ParseResult FromError(CommandError error, string reason)
-            => new ParseResult(null, null, error, reason);
+            => new ParseResult(null, null, null, error, reason);
         public static ParseResult FromError(IResult result)
-            => new ParseResult(null, null, result.Error, result.ErrorReason);
+            => new ParseResult(null, null, null, result.Error, result.ErrorReason);
 
         public override string ToString() => IsSuccess ? "Success" : $"{Error}: {ErrorReason}";
         private string DebuggerDisplay => IsSuccess ? $"Success ({ArgValues.Count}{(ParamValues.Count > 0 ? $" +{ParamValues.Count} Values" : "")})" : $"{Error}: {ErrorReason}";