func string_split()

in starlark/library.go [2044:2090]

• 40 lines of code
• 12 McCabe index (conditional complexity)

func string_split(_ *Thread, b *Builtin, args Tuple, kwargs []Tuple) (Value, error) {
	recv := string(b.Receiver().(String))
	var sep_ Value
	maxsplit := -1
	if err := UnpackPositionalArgs(b.Name(), args, kwargs, 0, &sep_, &maxsplit); err != nil {
		return nil, err
	}

	var res []string

	if sep_ == nil || sep_ == None {
		// special case: split on whitespace
		if maxsplit < 0 {
			res = strings.Fields(recv)
		} else if b.Name() == "split" {
			res = splitspace(recv, maxsplit)
		} else { // rsplit
			res = rsplitspace(recv, maxsplit)
		}

	} else if sep, ok := AsString(sep_); ok {
		if sep == "" {
			return nil, fmt.Errorf("split: empty separator")
		}
		// usual case: split on non-empty separator
		if maxsplit < 0 {
			res = strings.Split(recv, sep)
		} else if b.Name() == "split" {
			res = strings.SplitN(recv, sep, maxsplit+1)
		} else { // rsplit
			res = strings.Split(recv, sep)
			if excess := len(res) - maxsplit; excess > 0 {
				res[0] = strings.Join(res[:excess], sep)
				res = append(res[:1], res[excess:]...)
			}
		}

	} else {
		return nil, fmt.Errorf("split: got %s for separator, want string", sep_.Type())
	}

	list := make([]Value, len(res))
	for i, x := range res {
		list[i] = String(x)
	}
	return NewList(list), nil
}