func (bracket Bracket) evalSlice(env Env, val reflect.Value) (interface{}, error) {
items, err := Evals(env, bracket.expr...)
if err != nil {
return nil, err
}
indexs, err := bracket.computeIndexs(val, items)
if err != nil {
return nil, err
}
switch len(indexs) {
case 2:
v := val.Slice(indexs[0], indexs[1])
return bracket.inter(v), nil
case 3:
v := val.Slice3(indexs[0], indexs[1], indexs[2])
return bracket.inter(v), nil
}
return nil, fmt.Errorf("Index for slice %v[%v] is invalid",
bracket.obj, bracket.expr)
}