Struct Graph

pub struct Graph { /* private fields */ }

Implementations

impl Graph

pub fn append(&mut self, input: &str) -> Result<(), GraphHandlerError>

Parses the given GDL string and updates the graph state.

Example

use gdl::Graph;

let mut graph = "(alice),(bob)".parse::<gdl::Graph>().unwrap();

graph.append("(alice)-[:KNOWS]->(bob)");
graph.append("(bob)-[:KNOWS]->(eve)");

assert_eq!(graph.node_count(), 3);
assert_eq!(graph.relationship_count(), 2);

pub fn node_count(&self) -> usize

Returns the number of nodes in the graph.

Example

use gdl::Graph;

let graph = "()-->()-->()-->()".parse::<gdl::Graph>().unwrap();

assert_eq!(graph.node_count(), 4);

pub fn relationship_count(&self) -> usize

Returns the number of relationships in the graph.

Example

use gdl::Graph;

let graph = "()-->()-->()-->()".parse::<gdl::Graph>().unwrap();

assert_eq!(graph.relationship_count(), 3);

pub fn get_node(&self, variable: &str) -> Option<&Node>

Returns the node for the given variable.

Example:

use gdl::Graph;
use gdl::CypherValue;
use std::rc::Rc;

let graph = "(n0:A:B { foo: 42, bar: 1337 })".parse::<gdl::Graph>().unwrap();

let n0 = graph.get_node("n0").unwrap();

assert_eq!(n0.variable(), String::from("n0"));
assert_eq!(n0.labels().collect::<Vec<_>>(), vec!["A", "B"]);
assert_eq!(n0.property_value("foo").unwrap(), &CypherValue::from(42));

pub fn get_relationship(&self, variable: &str) -> Option<&Relationship>

Returns the relationship for the given variable.

Example:

use gdl::Graph;
use gdl::CypherValue;
use std::rc::Rc;

let graph = "()-[r0:REL { foo: 42, bar: 13.37 }]->()".parse::<gdl::Graph>().unwrap();

let r0 = graph.get_relationship("r0").unwrap();

assert_eq!(r0.variable(), String::from("r0"));
assert_eq!(r0.rel_type(), Some("REL"));
assert_eq!(r0.property_value("bar").unwrap(), &CypherValue::from(13.37));

pub fn nodes(&self) -> impl Iterator<Item = &Node>

Returns an iterator of nodes contained in the graph.

Example

use gdl::Graph;

let graph = "(a),(b),(c)".parse::<gdl::Graph>().unwrap();

for node in graph.nodes() {
    println!("{:?}", node);
}

pub fn relationships(&self) -> impl Iterator<Item = &Relationship>

Returns an iterator of relationships contained in the graph.

Example

use gdl::Graph;

let graph = "(a)-->(b)-->(c)".parse::<gdl::Graph>().unwrap();

for relationship in graph.relationships() {
    println!("{:?}", relationship);
}

Trait Implementations

impl Default for Graph

fn default() -> Graph

Returns the “default value” for a type.

impl FromStr for Graph

fn from_str(input: &str) -> Result<Self, Self::Err>

Creates a new graph from the given GDL string.

Example

use gdl::Graph;
use gdl::CypherValue;
use std::rc::Rc;

let graph =
    "(alice:Person { age: 23 }),
    (bob:Person { age: 42 }),
    (alice)-[r:KNOWS]->(bob)".parse::<gdl::Graph>().unwrap();
     

assert_eq!(graph.node_count(), 2);
assert_eq!(graph.relationship_count(), 1);

let alice = graph.get_node("alice").unwrap();

assert_eq!(alice.property_value("age"), Some(&CypherValue::from(23)));

let relationship = graph.get_relationship("r").unwrap();
assert_eq!(relationship.rel_type(), Some("KNOWS"));

type Err = GraphHandlerError

The associated error which can be returned from parsing.