TypeScript function evaluation, but lazy. Cool like P. Swayze.
Imagine a program that takes two arguments a and b and calculates four
values c, d, e, and f with the following formulas:
c = a + b
d = a * b
e = c + d
f = c * d
For the sake of this example, imagine the + and * operations are very
expensive. The code below shows how swayze can help optimize this program:
// import the swayze DSL functions
import { arg, fun } from "./mod.ts";
// define some pure functions that are potentially expensive
const add = (x: number, y: number) => a + b;
const mul = (x: number, y: number) => a * b;
// define the DAG with two arguments a and b, and derived values c, d, e, and f
const a = arg(0);
const b = arg(0);
const c = fun(add, a, b);
const d = fun(mul, a, b);
const e = fun(add, c, d);
const f = fun(mul, c, d);
// set new argument values
a.set(2);
b.set(3);
// calculates values c, d, and e for the first time
e.get();
// calculates value f and uses cached values of c and d
f.get();
// uses cached values of e and f
e.get();
f.get();