kevingurney opened a new pull request, #37981: URL: https://github.com/apache/arrow/pull/37981
### Rationale for this change In order to make the [`arrow::PrettyPrint`](https://github.com/apache/arrow/blob/7667b81bffcb5b361fab6d61c42ce396d98cc6e1/cpp/src/arrow/pretty_print.h#L101) functionality for `arrow::Array` more flexible, it would be useful to be to specify a custom `Array` element delimiter other than `","`. For example, the MATLAB interface wraps the Arrow C++ libraries and being able to specify a custom `Array` element delimiter, would make it possible to make the display of MATLAB `arrow.array.Array` objects more MATLAB-like. For the MATLAB interface, we would like to enable display that looks something like the following (note the ` | ` between individual `Array` elements: ```matlab % Make a MATLAB array. >> A = 1:5 A = 1 2 3 4 5 % Make an Arrow array from the MATLAB array. >> B = arrow.array(A) B = [ 1 | 2 | 3 | 4 | 5 ] ``` In order to support custom `Array` element delimiters, this pull request adds a new option `array_element_delimiter` with type `std::string` to the [`arrow::PrettyPrintOptions`](https://github.com/apache/arrow/blob/7667b81bffcb5b361fab6d61c42ce396d98cc6e1/cpp/src/arrow/pretty_print.h#L35) struct. In a future pull request, we would like to enable more `PrettyPrintOptions` like custom closing and opening delimiters for `arrow::Array` (e.g. "<" rather than "[" and ">" rather than "]"). ### What changes are included in this PR? 1. Added a new option `array_element_delimiter` with type `std::string` to the [`arrow::PrettyPrintOptions`](https://github.com/apache/arrow/blob/7667b81bffcb5b361fab6d61c42ce396d98cc6e1/cpp/src/arrow/pretty_print.h#L35) struct. This option allows the user to specify any string value as the delimiter to distinguish between individual elements of an `arrow::Array` when being printed using [`arrow::PrettyPrint`](https://github.com/apache/arrow/blob/7667b81bffcb5b361fab6d61c42ce396d98cc6e1/cpp/src/arrow/pretty_print.h#L101). ### Are these changes tested? Yes. 1. Added new tests `PrimitiveTypeCustomArrayElementDelimiter` and `ChunkedArrayPrimitiveTypeCustomArrayDelimiter` to `pretty_print_test.cc`. 2. All existing `PrettyPrint`-related C++ tests pass. ### Are there any user-facing changes? Yes. 1. User's can now specify a custom `Array` element delimiter when printing `arrow::Array`s using [`arrow::PrettyPrint`](https://github.com/apache/arrow/blob/7667b81bffcb5b361fab6d61c42ce396d98cc6e1/cpp/src/arrow/pretty_print.h#L101) by specifying a value for the `array_element_delimiter` property of [`arrow::PrettyPrintOptions`](https://github.com/apache/arrow/blob/7667b81bffcb5b361fab6d61c42ce396d98cc6e1/cpp/src/arrow/pretty_print.h#L35). ### Future Directions 1. To keep this pull request small and focused, I intentionally chose not to include changes related to specifying custom opening and closing `Array` delimiters (e.g. use `<` and `>` instead of `[` and `]`). I've captured the idea of supporting custom opening and closing `Array` delimiters in #37979. I will follow up with a future PR to address this. ### Notes 1. This pull request was motivated by our desire to improve the display of Arrow related classes in the MATLAB interface, but it is hopefully a generic enough change that it may benefit other use cases too. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
