init

examples/loan.rs

@@ -0,0 +1,55 @@
+use owl::{db::model::person::Person, prelude::*};
+#[relation("receiver", Person, "payer", Person, RelationKind::Bidirectional)]
+pub struct LoanRelation {
+    debt: f64,
+}
+
+pub fn lend_money(who: &Model<Person>, from: &Model<Person>, amount: f64, db: &Database) {
+    LoanRelation { debt: amount }.add(who, from, None, db)
+}
+
+pub fn pay_off(who: &Model<Person>, to: &Model<Person>, amount: f64, db: &Database) {
+    let mut loan = LoanRelation::get(who, to, db).unwrap();
+    loan.write(db, |loan| {
+        loan.alter_meta(|x: &mut _| {
+            x.debt -= amount;
+        });
+    });
+}
+
+pub fn main() {
+    env_logger::init();
+
+    let db = Database::filesystem("./db");
+    let p = db.save(Person::new_id("myperson", "first", "last"));
+    let p2 = db.save(Person::new_id("secperson", "second", "last"));
+    let banker = db.save(Person::new_id("banker", "boss", "bank"));
+
+    lend_money(&p, &banker, 250.0, &db);
+
+    lend_money(&p2, &p, 100.0, &db);
+
+    lend_money(&p2, &banker, 150.0, &db);
+
+    let financer: Vec<_> = LoanRelation::get_payer_of(&p2, &db)
+        .into_iter()
+        .map(|x| LoanRelation::payer(&x.dereference(&db), &db))
+        .map(|x| x.read().first_name.current().cloned().unwrap())
+        .collect();
+    println!(
+        "{} is financed by {:?}",
+        p2.read().first_name.current().unwrap(),
+        financer
+    );
+
+    let brokers = LoanRelation::get_receiver_of(&p, &db);
+    dbg!(&brokers);
+    let brokers = dereference(&brokers, &db);
+
+    brokers.iter().for_each(|x| println!("{:?}", x.read()));
+
+    pay_off(&p2, &p, 100.0, &db);
+
+    let brokers = dereference(&LoanRelation::get_receiver_of(&p, &db), &db);
+    brokers.iter().for_each(|x| println!("{:?}", x.read()));
+}