[C++][Compute] Formalize "metafunction" concept

[asfimport]

A metafunction is a function that provides the Execute API but does not contain any kernels. Such functions can also handle non-Array/Scalar inputs like RecordBatch or Table.

This will enable bindings to invoke such functions (like take, filter) like

call_function('take', [table, indices])

Reporter: Wes McKinney / @wesm
Assignee: Wes McKinney / @wesm

Related issues:

• [C++] C++ array kernels framework and execution buildout (umbrella issue) (is a child of)
• [C++] Refactor filter/take kernels to use Datum instead of overloads (is related to)
• [C++] compute::CallFunction can't Filter/Take with ChunkedArray (is related to)

PRs and other links:

• GitHub Pull Request #7318

_{Note: This issue was originally created as ARROW-8917. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Issue resolved by pull request 7318
#7318