Crate substrait

Substrait: Cross-Language Serialization for Relational Algebra

Serialization and deserialization

This crate provides generated types to serialize and deserialize Substrait data.

Protobuf

Protobuf serialization and deserialization are provided via prost in the proto module.

Example

Serialize and deserialize a plan

use prost::Message;
use substrait::proto::Plan;

let plan = Plan::default();

// Serialize the plan
let encoded = plan.encode_to_vec();

// Deserialize the buffer to a Plan
let decoded = Plan::decode(encoded.as_slice())?;

assert_eq!(plan, decoded);

Serde support

The serde feature generates serde implementations that match the Protobuf JSON Mapping via pbjson.

Example

Deserialize a plan version using the serde feature

use substrait::proto::Version;

let version_json = r#"{
  "minorNumber": 21
}"#;

let version = serde_json::from_str::<Version>(version_json)?;
assert_eq!(
  version,
  Version {
    minor_number: 21,
    ..Default::default()
  }
);

Text

Substrait defines a YAML schema for extensions. Types with serialization and deserialization support for these are provided via typify in the text module.

Example

Read a simple extension

use substrait::text::simple_extensions::SimpleExtensions;

let simple_extension_yaml = r#"
%YAML 1.2
---
scalar_functions:
  -
    name: "add"
    description: "Add two values."
    impls:
      - args:
         - name: x
           value: i8
         - name: y
           value: i8
        options:
          overflow:
            values: [ SILENT, SATURATE, ERROR ]
        return: i8
"#;

let simple_extension = serde_yaml::from_str::<SimpleExtensions>(simple_extension_yaml)?;

assert_eq!(simple_extension.scalar_functions.len(), 1);
assert_eq!(simple_extension.scalar_functions[0].name, "add");

Modules

• extensionsextensions
  Substrait core extensions
• parseparse
  Parsing of Substrait data.
• proto
  Generated types for the protobuf substrait package.
• text
  Generated types for text-based definitions.
• version
  Substrait version information.