From e6918187568dbd01842d8d1d2c808ce16a894239 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 21 Apr 2024 13:54:28 +0200 Subject: Adding upstream version 18.2.2. Signed-off-by: Daniel Baumann --- src/arrow/ruby/red-gandiva/README.md | 68 ++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 src/arrow/ruby/red-gandiva/README.md (limited to 'src/arrow/ruby/red-gandiva/README.md') diff --git a/src/arrow/ruby/red-gandiva/README.md b/src/arrow/ruby/red-gandiva/README.md new file mode 100644 index 000000000..ac6f88c58 --- /dev/null +++ b/src/arrow/ruby/red-gandiva/README.md @@ -0,0 +1,68 @@ + + +# Red Gandiva - Gandiva Ruby + +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](https://wiki.gnome.org/action/show/Projects/GObjectIntrospection) is a middleware for language bindings of C library. GObject Introspection can generate language bindings automatically at runtime. + +Red Gandiva uses [Gandiva GLib](https://github.com/apache/arrow/tree/master/c_glib/gandiva-glib) and [gobject-introspection gem](https://rubygems.org/gems/gobject-introspection) to generate Ruby bindings of Gandiva. + +Gandiva GLib is a C wrapper for [Gandiva C++](https://github.com/apache/arrow/tree/master/cpp/gandiva). 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 + +Install Gandiva GLib before install Red Gandiva. See [Apache Arrow install document](https://arrow.apache.org/install/) for details. + +Install Red Gandiva after you install Gandiva GLib: + +```text +% gem install red-gandiva +``` + +## Usage + +```ruby +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 +``` -- cgit v1.2.3