Enum Value

Source

pub enum Value {
    Node(NodeId),
    String(String),
    Integer(i64),
    Float(f64),
    Boolean(bool),
    DateTime(String),
    Typed {
        value: String,
        datatype: String,
    },
    LangString {
        value: String,
        lang: String,
    },
    Bytes(Vec<u8>),
    Json(Value),
    Null,
}

Expand description

Represents the object of a (subject, predicate, object) triple.

A Value can be either a reference to another node in the graph (creating a link) or a literal value of various types (string, number, boolean, etc.).

§Examples

Creating a string literal:

use aingle_graph::Value;

let val = Value::literal("Alice");
assert!(val.is_literal());
assert_eq!(val.as_string(), Some("Alice"));

Creating a node reference:

use aingle_graph::{Value, NodeId};

let val = Value::node(NodeId::named("user:bob"));
assert!(val.is_node());

Creating numeric values:

use aingle_graph::Value;

let age = Value::integer(30);
assert_eq!(age.as_integer(), Some(30));

let score = Value::float(98.5);
assert_eq!(score.as_float(), Some(98.5));

Creating a typed literal:

use aingle_graph::Value;

let val = Value::typed("2024-01-01", "xsd:date");

Variants§

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Node(NodeId)

A reference to another node in the graph, linking two subjects together.

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String(String)

A UTF-8 string literal.

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Integer(i64)

A 64-bit signed integer literal.

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Float(f64)

A 64-bit floating-point literal.

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Boolean(bool)

A boolean literal.

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DateTime(String)

A date-time literal, typically stored as an ISO 8601 string.

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Typed

A literal with an explicit datatype URI, similar to RDF typed literals.

Fields

§value: String

§datatype: String

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LangString

A string literal with a language tag.

Fields

§value: String

§lang: String

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Bytes(Vec<u8>)

A blob of binary data.

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Json(Value)

A JSON value, allowing for complex, nested data structures as objects.

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Null

The null value.

Implementations§

Source §

impl Value

Source

pub fn literal(s: impl Into<String>) -> Self

Creates a new string literal Value.

§Examples

use aingle_graph::Value;

let val = Value::literal("Hello, World!");
assert_eq!(val.as_string(), Some("Hello, World!"));

Source

pub fn node(node: NodeId) -> Self

Creates a Value that is a reference to another NodeId.

This creates a link between two nodes in the graph.

§Examples

use aingle_graph::{Value, NodeId};

let val = Value::node(NodeId::named("user:bob"));
assert!(val.is_node());
assert_eq!(val.as_node(), Some(&NodeId::named("user:bob")));

Source

pub fn integer(n: i64) -> Self

Creates a new integer Value.

§Examples

use aingle_graph::Value;

let val = Value::integer(42);
assert_eq!(val.as_integer(), Some(42));

Source

pub fn float(f: f64) -> Self

Creates a new float Value.

§Examples

use aingle_graph::Value;

let val = Value::float(3.14);
assert_eq!(val.as_float(), Some(3.14));

Source

pub fn boolean(b: bool) -> Self

Creates a new boolean Value.

§Examples

use aingle_graph::Value;

let val = Value::boolean(true);
assert_eq!(val.as_boolean(), Some(true));

Source

pub fn datetime(dt: impl Into<String>) -> Self

Creates a new date-time Value.

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pub fn typed(value: impl Into<String>, datatype: impl Into<String>) -> Self

Creates a new typed literal Value.

Typed literals have an associated datatype URI, similar to RDF typed literals.

§Examples

use aingle_graph::Value;

let date = Value::typed("2024-01-01", "xsd:date");
let custom = Value::typed("custom_value", "http://example.org/mytype");

Source

pub fn lang_string(value: impl Into<String>, lang: impl Into<String>) -> Self

Creates a new language-tagged string Value.

Language-tagged strings are useful for internationalization, allowing you to store the same text in multiple languages.

§Examples

use aingle_graph::Value;

let english = Value::lang_string("Hello", "en");
let spanish = Value::lang_string("Hola", "es");
let french = Value::lang_string("Bonjour", "fr");

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pub fn bytes(data: Vec<u8>) -> Self

Creates a new bytes Value.

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pub fn json(value: Value) -> Self

Creates a new JSON Value.

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pub fn null() -> Self

Creates a Null value.

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pub fn is_node(&self) -> bool

Returns true if the Value is a Node reference.

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pub fn is_literal(&self) -> bool

Returns true if the Value is a literal (i.e., not a Node or Null).

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pub fn is_null(&self) -> bool

Returns true if the Value is Null.

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pub fn as_node(&self) -> Option<&NodeId>

Returns a reference to the NodeId if the Value is a Node.

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pub fn as_string(&self) -> Option<&str>

Returns a string slice if the Value is a string-like literal.

Source

pub fn as_integer(&self) -> Option<i64>

Returns the i64 value if the Value is an Integer.

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pub fn as_float(&self) -> Option<f64>

Returns the f64 value if the Value is a Float or can be cast from Integer.

Source

pub fn as_boolean(&self) -> Option<bool>

Returns the bool value if the Value is a Boolean.

Source

pub fn to_bytes(&self) -> Vec<u8> ⓘ

Serializes the Value to a byte vector for storage.

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pub fn from_bytes(bytes: &[u8]) -> Option<Self>

Deserializes a Value from a byte slice.

Source

pub fn sort_key(&self) -> Vec<u8> ⓘ

Returns a byte vector suitable for lexicographical sorting in the database indexes.

This method generates a binary representation of the value that can be sorted lexicographically to maintain proper ordering in the database. Different value types are given different type tags to ensure correct cross-type ordering.