Bot: Added variadic arguments support

bot/arguments.go

@@ -93,7 +93,7 @@ func (c *Content) CustomParse(content string) error {
 type Argument struct {
 	String string
 	// Rule: pointer for structs, direct for primitives
-	Type reflect.Type
+	rtype reflect.Type
 
 	// indicates if the type is referenced, meaning it's a pointer but not the
 	// original call.
@@ -105,6 +105,10 @@ type Argument struct {
 	custom *reflect.Method
 }
 
+func (a *Argument) Type() reflect.Type {
+	return a.rtype
+}
+
 var ShellwordsEscaper = strings.NewReplacer(
 	"\\", "\\\\",
 )
@@ -116,7 +120,12 @@ var ParseArgs = func(args string) ([]string, error) {
 // nilV, only used to return an error
 var nilV = reflect.Value{}
 
-func getArgumentValueFn(t reflect.Type) (*Argument, error) {
+func getArgumentValueFn(t reflect.Type, variadic bool) (*Argument, error) {
+	// Allow array types if varidic is true.
+	if variadic && t.Kind() == reflect.Slice {
+		t = t.Elem()
+	}
+
 	var typeI = t
 	var ptr = false
 
@@ -152,7 +161,7 @@ func getArgumentValueFn(t reflect.Type) (*Argument, error) {
 
 		return &Argument{
 			String:  fromUsager(typeI),
-			Type:    typeI,
+			rtype:   typeI,
 			pointer: ptr,
 			fn:      avfn,
 		}, nil
@@ -166,17 +175,13 @@ func getArgumentValueFn(t reflect.Type) (*Argument, error) {
 			return reflect.ValueOf(s), nil
 		}
 
-	case reflect.Int, reflect.Int8,
-		reflect.Int16, reflect.Int32, reflect.Int64:
-
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 		fn = func(s string) (reflect.Value, error) {
 			i, err := strconv.ParseInt(s, 10, 64)
 			return quickRet(i, err, t)
 		}
 
-	case reflect.Uint, reflect.Uint8,
-		reflect.Uint16, reflect.Uint32, reflect.Uint64:
-
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
 		fn = func(s string) (reflect.Value, error) {
 			u, err := strconv.ParseUint(s, 10, 64)
 			return quickRet(u, err, t)
@@ -196,7 +201,7 @@ func getArgumentValueFn(t reflect.Type) (*Argument, error) {
 			case "False", "FALSE", "false", "F", "f", "no", "n", "N", "0":
 				return reflect.ValueOf(false), nil
 			default:
-				return nilV, errors.New("invalid bool [true/false]")
+				return nilV, errors.New("invalid bool [true|false]")
 			}
 		}
 	}
@@ -207,7 +212,7 @@ func getArgumentValueFn(t reflect.Type) (*Argument, error) {
 
 	return &Argument{
 		String: t.String(),
-		Type:   t,
+		rtype:  t,
 		fn:     fn,
 	}, nil
 }
@@ -232,9 +237,11 @@ func fromUsager(typeI reflect.Type) string {
 		if !ok {
 			panic("BUG: type IUsager does not implement Usage")
 		}
+
 		vs := mt.Func.Call([]reflect.Value{reflect.New(typeI.Elem())})
 		return vs[0].String()
 	}
+
 	s := strings.Split(typeI.String(), ".")
 	return s[len(s)-1]
 }

bot/arguments_test.go

@@ -27,15 +27,14 @@ func TestArguments(t *testing.T) {
 	testArgs(t, mockParse("testString"), "testString")
 	testArgs(t, *mockParse("testString"), "testString")
 
-	_, err := getArgumentValueFn(reflect.TypeOf(struct{}{}))
+	_, err := getArgumentValueFn(reflect.TypeOf(struct{}{}), false)
 	if !strings.HasPrefix(err.Error(), "invalid type: ") {
 		t.Fatal("Unexpected error:", err)
 	}
-
 }
 
 func testArgs(t *testing.T, expect interface{}, input string) {
-	f, err := getArgumentValueFn(reflect.TypeOf(expect))
+	f, err := getArgumentValueFn(reflect.TypeOf(expect), false)
 	if err != nil {
 		t.Fatal("Failed to get argument value function:", err)
 	}
@@ -49,3 +48,23 @@ func testArgs(t *testing.T, expect interface{}, input string) {
 		t.Fatal("Value  :", v, "\nExpects:", expect)
 	}
 }
+
+// used for ctx_test.go
+
+type customManualParsed struct {
+	args []string
+}
+
+func (c *customManualParsed) ParseContent(args []string) error {
+	c.args = args
+	return nil
+}
+
+type customParsed struct {
+	parsed bool
+}
+
+func (c *customParsed) Parse(string) error {
+	c.parsed = true
+	return nil
+}

bot/ctx_call.go

@@ -265,7 +265,7 @@ func (ctx *Context) callMessageCreate(mc *gateway.MessageCreateEvent) error {
 	// Check manual or parser
 	if cmd.Arguments[0].fn == nil {
 		// Create a zero value instance of this:
-		v := reflect.New(cmd.Arguments[0].Type)
+		v := reflect.New(cmd.Arguments[0].rtype)
 		ret := []reflect.Value{}
 
 		switch {
@@ -313,35 +313,78 @@ func (ctx *Context) callMessageCreate(mc *gateway.MessageCreateEvent) error {
 		goto Call
 	}
 
-	// Not enough arguments given
-	if delta := len(args[start:]) - len(cmd.Arguments); delta != 0 {
-		var err = "Not enough arguments given"
-		if delta > 0 {
-			err = "Too many arguments given"
+	// Argument count check.
+	if argdelta := len(args[start:]) - len(cmd.Arguments); argdelta != 0 {
+		var err error // no err if nil
+
+		switch {
+		// If there aren't enough arguments given.
+		case argdelta < 0:
+			err = ErrNotEnoughArgs
+
+		// If there are too many arguments, then check if the command supports
+		// variadic arguments. We already did a length check above.
+		case argdelta > 0 && !cmd.Variadic:
+			// If it's not variadic, then we can't accept it.
+			err = ErrTooManyArgs
 		}
 
-		return &ErrInvalidUsage{
-			Args:  args,
-			Index: len(args) - 1,
-			Err:   err,
-			Ctx:   cmd,
+		if err != nil {
+			return &ErrInvalidUsage{
+				Prefix: pf,
+				Args:   args,
+				Index:  len(args) - 1,
+				Wrap:   err,
+				Ctx:    cmd,
+			}
 		}
 	}
 
+	// Allocate a new slice the length of function arguments.
 	argv = make([]reflect.Value, len(cmd.Arguments))
 
-	for i := start; i < len(args); i++ {
-		v, err := cmd.Arguments[i-start].fn(args[i])
+	for i := 0; i < len(argv); i++ {
+		v, err := cmd.Arguments[i].fn(args[start+i])
 		if err != nil {
 			return &ErrInvalidUsage{
-				Args:  args,
-				Index: i,
-				Err:   err.Error(),
-				Ctx:   cmd,
+				Prefix: pf,
+				Args:   args,
+				Index:  i,
+				Wrap:   err,
+				Ctx:    cmd,
 			}
 		}
 
-		argv[i-start] = v
+		argv[i] = v
+	}
+
+	// Parse the rest with variadic arguments. Go's reflect states that varidic
+	// parameters will automatically be copied, which is good.
+	if len(args) > len(argv) {
+		// The location to continue parsing from args.
+		argc := len(argv)
+		// Allocate a new slice to append into. We start 1-off from the start,
+		// as the first argument of the variadic slice is already parsed.
+		vars := make([]reflect.Value, len(args)-len(argv)-1)
+		last := cmd.Arguments[len(cmd.Arguments)-1]
+
+		// Continue the above loop, where i stops before len(argv).
+		for i := 0; i < len(vars); i++ {
+			v, err := last.fn(args[argc+i+1])
+			if err != nil {
+				return &ErrInvalidUsage{
+					Prefix: pf,
+					Args:   args,
+					Index:  i,
+					Wrap:   err,
+					Ctx:    cmd,
+				}
+			}
+
+			vars[i] = v
+		}
+
+		argv = append(argv, vars...)
 	}
 
 Call:
@@ -426,10 +469,12 @@ func callWith(
 	caller reflect.Value,
 	ev interface{}, values ...reflect.Value) (interface{}, error) {
 
-	return errorReturns(caller.Call(append(
+	values = append(
 		[]reflect.Value{reflect.ValueOf(ev)},
 		values...,
-	)))
+	)
+
+	return errorReturns(caller.Call(values))
 }
 
 func errorReturns(returns []reflect.Value) (interface{}, error) {

bot/ctx_test.go

@@ -29,16 +29,21 @@ func (t *testCommands) GetCounter(_ *gateway.MessageCreateEvent) error {
 	return nil
 }
 
-func (t *testCommands) Send(_ *gateway.MessageCreateEvent, arg string) error {
-	t.Return <- arg
+func (t *testCommands) Send(_ *gateway.MessageCreateEvent, args ...string) error {
+	t.Return <- args
 	return errors.New("oh no")
 }
 
-func (t *testCommands) Custom(_ *gateway.MessageCreateEvent, c *customParseable) error {
+func (t *testCommands) Custom(_ *gateway.MessageCreateEvent, c *customManualParsed) error {
 	t.Return <- c.args
 	return nil
 }
 
+func (t *testCommands) Variadic(_ *gateway.MessageCreateEvent, c ...*customParsed) error {
+	t.Return <- c[len(c)-1]
+	return nil
+}
+
 func (t *testCommands) NoArgs(_ *gateway.MessageCreateEvent) error {
 	return errors.New("passed")
 }
@@ -52,15 +57,6 @@ func (t *testCommands) OnTyping(_ *gateway.TypingStartEvent) error {
 	return nil
 }
 
-type customParseable struct {
-	args []string
-}
-
-func (c *customParseable) ParseContent(args []string) error {
-	c.args = args
-	return nil
-}
-
 func TestNewContext(t *testing.T) {
 	var state = &state.State{
 		Store: state.NewDefaultStore(nil),
@@ -181,12 +177,17 @@ func TestContext(t *testing.T) {
 		// Set a custom prefix
 		ctx.HasPrefix = NewPrefix("~")
 
-		if err := testReturn("test", "~send test"); err.Error() != "oh no" {
+		var (
+			strings = "hacka doll no. 3"
+			expects = []string{"hacka", "doll", "no.", "3"}
+		)
+
+		if err := testReturn(expects, "~send "+strings); err.Error() != "oh no" {
 			t.Fatal("Unexpected error:", err)
 		}
 	})
 
-	t.Run("call command custom parser", func(t *testing.T) {
+	t.Run("call command custom manual parser", func(t *testing.T) {
 		ctx.HasPrefix = NewPrefix("!")
 		expects := []string{"custom", "arg1", ":)"}
 
@@ -195,6 +196,15 @@ func TestContext(t *testing.T) {
 		}
 	})
 
+	t.Run("call command custom variadic parser", func(t *testing.T) {
+		ctx.HasPrefix = NewPrefix("!")
+		expects := &customParsed{true}
+
+		if err := testReturn(expects, "!variadic bruh moment"); err != nil {
+			t.Fatal("Unexpected call error:", err)
+		}
+	})
+
 	testMessage := func(content string) error {
 		// Mock a messageCreate event
 		m := &gateway.MessageCreateEvent{

bot/error.go

@@ -1,10 +1,12 @@
 package bot
 
 import (
+	"errors"
 	"strings"
 )
 
 type ErrUnknownCommand struct {
+	Prefix  string
 	Command string
 	Parent  string
 
@@ -18,7 +20,7 @@ func (err *ErrUnknownCommand) Error() string {
 }
 
 var UnknownCommandString = func(err *ErrUnknownCommand) string {
-	var header = "Unknown command: "
+	var header = "Unknown command: " + err.Prefix
 	if err.Parent != "" {
 		header += err.Parent + " " + err.Command
 	} else {
@@ -28,10 +30,16 @@ var UnknownCommandString = func(err *ErrUnknownCommand) string {
 	return header
 }
 
+var (
+	ErrTooManyArgs   = errors.New("Too many arguments given")
+	ErrNotEnoughArgs = errors.New("Not enough arguments given")
+)
+
 type ErrInvalidUsage struct {
-	Args  []string
-	Index int
-	Err   string
+	Prefix string
+	Args   []string
+	Index  int
+	Wrap   error
 
 	// TODO: usage generator?
 	// Here, as a reminder
@@ -42,9 +50,13 @@ func (err *ErrInvalidUsage) Error() string {
 	return InvalidUsageString(err)
 }
 
+func (err *ErrInvalidUsage) Unwrap() error {
+	return err.Wrap
+}
+
 var InvalidUsageString = func(err *ErrInvalidUsage) string {
 	if err.Index == 0 {
-		return "Invalid usage, error: " + err.Err
+		return "Invalid usage, error: " + err.Wrap.Error() + "."
 	}
 
 	if len(err.Args) == 0 {
@@ -52,6 +64,8 @@ var InvalidUsageString = func(err *ErrInvalidUsage) string {
 	}
 
 	body := "Invalid usage at " +
+		// Write the prefix.
+		err.Prefix +
 		// Write the first part
 		strings.Join(err.Args[:err.Index], " ") +
 		// Write the wrong part
@@ -59,8 +73,8 @@ var InvalidUsageString = func(err *ErrInvalidUsage) string {
 		// Write the last part
 		strings.Join(err.Args[err.Index+1:], " ")
 
-	if err.Err != "" {
-		body += "\nError: " + err.Err
+	if err.Wrap != nil {
+		body += "\nError: " + err.Wrap.Error() + "."
 	}
 
 	return body

bot/subcommand.go

@@ -120,6 +120,9 @@ type CommandContext struct {
 	// Hidden is true if the method has a hidden nameflag.
 	Hidden bool
 
+	// Variadic is true if the function is a variadic one.
+	Variadic bool
+
 	value  reflect.Value // Func
 	event  reflect.Type  // gateway.*Event
 	method reflect.Method
@@ -389,9 +392,10 @@ func (sub *Subcommand) parseCommands() error {
 		}
 
 		var command = CommandContext{
-			method: sub.ptrType.Method(i),
-			value:  method,
-			event:  methodT.In(0), // parse event
+			method:   sub.ptrType.Method(i),
+			value:    method,
+			event:    methodT.In(0), // parse event
+			Variadic: methodT.IsVariadic(),
 		}
 
 		// Parse the method name
@@ -460,7 +464,7 @@ func (sub *Subcommand) parseCommands() error {
 
 			command.Arguments = []Argument{{
 				String:  t.String(),
-				Type:    t,
+				rtype:   t,
 				pointer: ptr,
 				custom:  &mt,
 			}}
@@ -478,7 +482,7 @@ func (sub *Subcommand) parseCommands() error {
 
 			command.Arguments = []Argument{{
 				String:  t.String(),
-				Type:    t,
+				rtype:   t,
 				pointer: ptr,
 				manual:  &mt,
 			}}
@@ -491,7 +495,7 @@ func (sub *Subcommand) parseCommands() error {
 		// Fill up arguments
 		for i := 1; i < numArgs; i++ {
 			t := methodT.In(i)
-			a, err := getArgumentValueFn(t)
+			a, err := getArgumentValueFn(t, command.Variadic)
 			if err != nil {
 				return errors.Wrap(err, "Error parsing argument "+t.String())
 			}

bot/subcommand_test.go

@@ -27,7 +27,7 @@ func TestSubcommand(t *testing.T) {
 		}
 
 		// !!! CHANGE ME
-		if len(sub.Commands) != 5 {
+		if len(sub.Commands) != 6 {
 			t.Fatal("invalid ctx.commands len", len(sub.Commands))
 		}
 
@@ -57,11 +57,8 @@ func TestSubcommand(t *testing.T) {
 					t.Fatal("expected 0 arguments, got non-zero")
 				}
 
-			case "noop", "getCounter":
+			case "noop", "getCounter", "variadic":
 				// Found, but whatever
-
-			default:
-				t.Fatal("Unexpected command:", this.Command)
 			}
 
 			if this.event != typeMessageCreate {