[GitHub] [arrow] felipecrv opened a new issue, #33872: Replace shared_ptr creation hack before AppendScalarImpl instantiation

["felipecrv (via GitHub)" <gi...@apache.org>]

felipecrv opened a new issue, #33872:
URL: https://github.com/apache/arrow/issues/33872

   ### Describe the enhancement requested
   
   `AppendScalarImpl` was created for appending scalars based on a contiguous array of `std::shared_ptr<Scalar>`, so when a single `Scalar` reference is passed, a dummy `shared_ptr` is created before the instantiation of `AppendScalarImpl`.
   
   ```cpp
     std::shared_ptr<Scalar> shared{const_cast<Scalar*>(&scalar), [](Scalar*) {}};
     return AppendScalarImpl{&shared, &shared + 1, n_repeats, this}.Convert();
   ```
   
   This seems non-idiomatic [1] and likely inefficient as a control block needs to be heap-allocated for the `shared_ptr`. An alternative way (that simplifies `AppendScalarImpl` as well) is a custom iterator class the wraps the source iterator with an extra dereference operation.
   
   [1] Pointers to `shared_ptr` as class members are a bad precedent
   
   ### Component(s)
   
   C++


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[GitHub] [arrow] lidavidm closed issue #33872: [C++] Replace shared_ptr creation hack before AppendScalarImpl instantiation

["lidavidm (via GitHub)" <gi...@apache.org>]

lidavidm closed issue #33872: [C++] Replace shared_ptr creation hack before AppendScalarImpl instantiation
URL: https://github.com/apache/arrow/issues/33872


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