[C++][arrow::compute::Expression]Is there a way to construct arrow::compute::Expression from the evaluated Expression string?

[1057445597 <10...@qq.com>]

I noticed that the class arrow::compute::Expression have a ToString member function, is there good way from a string mathematical Expression to construct a arrow::compute::Expression?


(subtract(a210, multiply(divide(a210, 203), 203)) == 0)




1057445597
1057445597@qq.com



 

Re: [C++][arrow::compute::Expression]Is there a way to construct arrow::compute::Expression from the evaluated Expression string?

[Weston Pace <we...@gmail.com>]

No.  There is no text format for expressions or related parser.  I believe
the Substrait project still would like to invent a text format someday and
expressions would need to be a part of that so I think there is some
interest.

In the meantime a PR here (or at the Substrait project to align on spec)
would be welcome.

As a workaround there are C++ utilities for creating expressions:

call("subtract", {field_ref("a210"), call("multiply", {call("divide",
{field_ref("a210"), literal(203)}), literal(203)})})

There is also Isthmus which can go from SQL -> Substrait and then you we
could pretty easily expose Substrait expression parsing as its own
standalone thing (returning arrow::compute::Expression)

On Mon, Jul 18, 2022 at 3:52 AM 1057445597 <10...@qq.com> wrote:

> I noticed that the class arrow::compute::Expression have a ToString member
> function, is there good way from a string mathematical Expression to
> construct a arrow::compute::Expression?
>
> (subtract(a210, multiply(divide(a210, 203), 203)) == 0)
>
> ------------------------------
> 1057445597
> 1057445597@qq.com
>
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