object

var Builtins = []struct {
	Name    string
	Builtin *Builtin
}{
	{
		BuiltinFuncNameLen,
		&Builtin{Fn: func(args ...Object) Object {
			if len(args) != 1 {
				return newError("wrong number of arguments. got=%d, want=1",
					len(args))
			}

			switch arg := args[0].(type) {
			case *Array:
				return &Integer{Value: int64(len(arg.Elements))}
			case *String:
				return &Integer{Value: int64(len(arg.Value))}
			default:
				return newError("argument to %q not supported, got %s",
					BuiltinFuncNameLen, args[0].Type())
			}
		},
		},
	},
	{
		BuiltinFuncNamePuts,
		&Builtin{Fn: func(args ...Object) Object {
			for _, arg := range args {
				fmt.Println(arg.Inspect())
			}

			return nil
		},
		},
	},
	{
		BuiltinFuncNameFirst,
		&Builtin{Fn: func(args ...Object) Object {
			if len(args) != 1 {
				return newError("wrong number of arguments. got=%d, want=1",
					len(args))
			}
			if args[0].Type() != ArrayObj {
				return newError("argument to %q must be %s, got %s",
					BuiltinFuncNameFirst, ArrayObj, args[0].Type())
			}

			arr := args[0].(*Array)
			if len(arr.Elements) > 0 {
				return arr.Elements[0]
			}

			return nil
		},
		},
	},
	{
		BuiltinFuncNameLast,
		&Builtin{Fn: func(args ...Object) Object {
			if len(args) != 1 {
				return newError("wrong number of arguments. got=%d, want=1",
					len(args))
			}
			if args[0].Type() != ArrayObj {
				return newError("argument to %q must be %s, got %s",
					BuiltinFuncNameLast, ArrayObj, args[0].Type())
			}

			arr := args[0].(*Array)
			length := len(arr.Elements)
			if length > 0 {
				return arr.Elements[length-1]
			}

			return nil
		},
		},
	},
	{
		BuiltinFuncNameRest,
		&Builtin{Fn: func(args ...Object) Object {
			if len(args) != 1 {
				return newError("wrong number of arguments. got=%d, want=1",
					len(args))
			}
			if args[0].Type() != ArrayObj {
				return newError("argument to %q must be %s, got %s",
					BuiltinFuncNameRest, ArrayObj, args[0].Type())
			}

			arr := args[0].(*Array)
			length := len(arr.Elements)
			if length > 0 {
				newElements := make([]Object, length-1, length-1)
				copy(newElements, arr.Elements[1:length])
				return &Array{Elements: newElements}
			}

			return nil
		},
		},
	},
	{
		BuiltinFuncNamePush,
		&Builtin{Fn: func(args ...Object) Object {
			if len(args) != 2 {
				return newError("wrong number of arguments. got=%d, want=2",
					len(args))
			}
			if args[0].Type() != ArrayObj {
				return newError("argument to %q must be %s, got %s",
					BuiltinFuncNamePush, ArrayObj, args[0].Type())
			}

			arr := args[0].(*Array)
			length := len(arr.Elements)

			newElements := make([]Object, length+1, length+1)
			copy(newElements, arr.Elements)
			newElements[length] = args[1]

			return &Array{Elements: newElements}
		},
		},
	},
	{
		BuiltinFuncNamePrint,
		&Builtin{Fn: func(args ...Object) Object {
			if len(args) != 1 {
				return newError("wrong number of arguments. got=%d, want=1",
					len(args))
			}
			if args[0].Type() != StringObj {
				return newError("argument to %q must be %s, got %s",
					BuiltinFuncNamePrint, ArrayObj, args[0].Type())
			}

			s := args[0].(*String)
			fmt.Println(s)

			return nil
		},
		},
	},
}