felixeder/turing.js

Turing.js is an Event-Driven-Language-Design-API based on the definition of a turing machine.

Turing.js

Turing.js is an Event-Driven-Language-Design-API based on the definition of a turing machine.

A Turing machine is an abstract machine that manipulates symbols on a strip of tape according to a table of rules. The machine operates on an infinite memory tape divided into discrete cells. The machine positions its head over a cell and "reads" the symbol there. Then, as per the symbol and its present place in a finite table of user-specified instructions, the machine (i) writes a symbol (e.g. a digit or a letter from a finite alphabet) in the cell, then (ii) either moves the tape one cell left or right, then (iii) (as determined by the observed symbol and the machine's place in the table) either proceeds to a subsequent instruction or halts the computation.

Typescript & Typings

Turing.js is written in and is designed to be used in Typescript, this means that Turing.js will always include its own typings. Because Turing.js comes with its own typings it lends it self very well to editors such as vs code that utilizes typings in both typescript and javascript to improve intellisense.

Links & Install

Install: npm i --save turingjs

Playground: https://runkit.com/olian04/turing-js-demo

Docs: https://olian04.github.io/Turing.js/

Demo

/* Super simple counter */
import { Language } from 'turingjs';

new Language<{ sum: number }>()
    .token({
        '+': state => { state.data.sum++ },
        '-': state => { state.data.sum-- }
    })
    .data({
        sum: 0
    })
    .run('++-+++--')
    .then(state => console.log(state.data.sum)/* 2 */);
    

---

/* The full Brainfuck language */
import { Language, GetTagFunction, Skip } from 'turingjs';

// Step 1: Define a new language
let brainfuck = new Language<{ in: string[], out: string[], loops: number[] }>()
    .token({
        '+': state => { state.stack[state.index]++ },
        '-': state => { state.stack[state.index]-- },
        '>': state => { state.index++ },
        '<': state => { state.index-- },
        ',': state => { state.stack[state.index] = state.data.in.shift().charCodeAt(0) },
        '.': state => { state.data.out.push(String.fromCharCode(state.stack[state.index])) },
        ']': (state, token) => { state.tokenPointer = state.data.loops.pop() - 1 },
        '[': (state, token) => {
            if (state.stack[state.index] === 0) {
                return Skip.until.balanced('[', ']', 1);
            }
            state.data.loops.push(token.position)
        }
    })
    .on('eof', state => state.data.loops.length === 0)
    .data({ in: [], out: [], loops: [] });

// Step 2: Run some code in the new language    
brainfuck
    .data({ in: 'ABC'.split('') })
    .run('+++[->,.+++.<]')
    .then(finalState => console.log(finalState.data.out.join(''))/* ADBECF */)
    .catch(error => console.log(error));

// Same thing as step 2, but using a tag function instead
let bf = GetTagFunction(brainfuck); //  Create tag function
let finalState = bf`+++[->,.+++.<]${{ in: 'ABC'.split('') }}`; // Run some code
console.log(finalState.data.out.join('')); // Get the output: ADBECF 

Developing

Built with

• Typescript
• Lodash

Tested with

• ts-node
• Mocha
• chai

Prerequisites

• Git
• Node.js

Setting up dev

git clone [email protected]:Olian04/Turing.js.git
cd Turing.js
npm install

Building

npm run build

Testing

npm run test

Publishing

Refer to: https://www.tsmean.com/articles/how-to-write-a-typescript-library/

Api reference

At the core of every Turing.js language lies a Language object, this object keeps track of what rules your language abides by. It is also this Language object that takes care of executing code written in your new language.

The Language object has 4 functions, each with several overloads, token, data, on, and run.

Function	Description
token	Adds TokenHandlers, these are the bread and butter of your languages grammar.
data	Provides a way of adding custom state properties to your language's interpreter.
on	Adds event handlers for various events fired during an execution of code.
run	Runs some code written in your new language.

For further reference please see the auto generated docs.

Credits

• Logo: https://logomakr.com/6LYfIX