[ARROW-13025] [C++][Compute] Enhance FunctionOptions with equality, debug representability, and serializability

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 5.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/28738
• Assignee: David Li
• Reporter: Ben Kietzman
• Created: 09/Jun/21 16:27
• Updated: 11/Jan/23 08:30
• Resolved: 30/Jun/21 18:23

Description

Currently the FunctionOptions interface is entirely opaque. It would be useful to add

• equality comparability

      bool FunctionOptions::Equals(const FunctionOptions& other) const
      

• debug representation

      std::string FunctionOptions::ToString() const
      

• serializability

      Status FunctionOptions::Serialize(io::OutputStream*) const
  
      Result<std::unique_ptr<FunctionOptions>>
          FunctionOptions::Deserialize(io::InputStream*)
      

  (or similar)

These are already implemented for common instances of FunctionOptions in expression.cc, since Expression has the above capabilities and may contain a FunctionOptions. Making these explicit virtual functions will formalize this ad-hoc
code and expose it for direct unit testing.

As an added bonus, if options can serialize themselves to JSON then that can be used by Python and other bindings to generate wrappers instead of the current hand-written listing of wrapper classes for each FunctionOptions subclass

Issue Links

• is a child of: ARROW-8894 [C++] C++ array kernels framework and execution buildout (umbrella issue)
• links to: GitHub Pull Request #10511