Method simplified_to

cpp/src/arrow/compute/expression.cc:1221–1245

The given expression simplifies to `value` if the inequality target is not nullable. Otherwise, it simplifies to either a call to true_unless_null or !true_unless_null.

  /// target is not nullable. Otherwise, it simplifies to either a
  /// call to true_unless_null or !true_unless_null.
  Result<Expression> simplified_to(const Expression& bound_target, bool value) const {
    if (!nullable) return literal(value);

    ExecContext exec_context;

    // Data may be null, so comparison will yield `value` - or null IFF the data was null
    //
    // true_unless_null is cheap; it purely reuses the validity bitmap for the values
    // buffer. Inversion is less cheap but we expect that term never to be evaluated
    // since invert(true_unless_null(x)) is not satisfiable.
    Expression::Call call;
    call.function_name = "true_unless_null";
    call.arguments = {bound_target};
    ARROW_ASSIGN_OR_RAISE(
        auto true_unless_null,
        BindNonRecursive(std::move(call),
                         /*insert_implicit_casts=*/false, &exec_context));
    if (value) return true_unless_null;

    Expression::Call invert;
    invert.function_name = "invert";
    invert.arguments = {std::move(true_unless_null)};
    return BindNonRecursive(std::move(invert),
                            /*insert_implicit_casts=*/false, &exec_context);
  }

  /// Simplify an `is_in` call against an inequality guarantee.
  ///