Red Gandiva is the Ruby bindings of Gandiva. Red Gandiva is based on GObject Introspection.
Gandiva is a toolset for compiling and evaluating expressions on Arrow data.
GObject Introspection is a middleware for language bindings of C library. GObject Introspection can generate language bindings automatically at runtime.
Red Gandiva uses Gandiva GLib and gobject-introspection gem to generate Ruby bindings of Gandiva.
Gandiva GLib is a C wrapper for Gandiva C++. GObject Introspection can't use Gandiva C++ directly. Gandiva GLib is a bridge between Gandiva C++ and GObject Introspection.
gobject-introspection gem is a Ruby bindings of GObject Introspection. Red Gandiva uses GObject Introspection via gobject-introspection gem.
Install Gandiva GLib before install Red Gandiva. See Apache Arrow install document for details.
Install Red Gandiva after you install Gandiva GLib:
% gem install red-gandiva
require "gandiva" table = Arrow::Table.new(:field1 => Arrow::Int32Array.new([1, 2, 3, 4]), :field2 => Arrow::Int32Array.new([11, 13, 15, 17])) schema = table.schema expression1 = schema.build_expression do |record| record.field1 + record.field2 end expression2 = schema.build_expression do |record, context| context.if(record.field1 > record.field2) .then(record.field1 / record.field2) .else(record.field1) end projector = Gandiva::Projector.new(schema, [expression1, expression2]) table.each_record_batch do |record_batch| outputs = projector.evaluate(record_batch) puts outputs.collect(&:values)) end