Term evaluation

plu-ts implements its own version of the CEK machine for the UPLC language. This allows any plu-ts term to be compiled to an UPLC Term and evaluated.

in order to evaluate a term we neet to import the CEK machine implemented in plu-ts

import { Machine } from "@harmoniclbs/plu-ts"

Machine is a class, because we can instantiate our own machines based on different protocol parameters.

however it also works as is using some default parameters.

if all we need is just to evaluate a term, then that works just fine.

Machine.evalSimple

The function that evaluates Terms is Machine.evalSimple, and that's literally all you need to evaluate a term.

Machine.evalSimple will return an UPLCTerm because UPLCTerms is what the machine is working with.

A UPLCTerm can be a lot of things, but if everything goes right and you expect a concrete value you'll only encounter UPLCConst instances, or some Lambda if you instead expect some functions.

If instead the plu-ts term you passed as argument fails the computation you will get back an instance of ErrorUPLC.

To test it we'll use the pfactorial we defined while introducing recursion

import { Machine } from "@harmoniclbs/plu-ts"
import { pfactorial } from "./pfactorial";

console.log(
    Machine.evalSimple(
        pfactorial.$( 0 )
    )
); // UPLCConst { _type: [0], _value: 1n }

console.log(
    Machine.evalSimple(
        pfactorial.$( 3 )
    )
); // UPLCConst { _type: [0], _value: 6n }

console.log(
    Machine.evalSimple(
        pfactorial.$( 5 )
    )
); // UPLCConst { _type: [0], _value: 120n }

console.log(
    Machine.evalSimple(
        pfactorial.$( 20 )
    )
); // UPLCConst { _type: [0], _value: 2432902008176640000nn }

Machine.evalSimple is especially useful if you need to test your plu-ts code; regardless of the testing framework of your choice you will be always able to run Machine.evalSimple.