Extending JavaScriptthe easy waySergi Mansilla, November 2012

@sergimansilla

JavaScript is popular

It is ASM for the web

CoffeeScriptLi

spyS

cript

JWacsFlapJax

Elm

Coco

FBJS JS11

Roy

Streamline JSTypeScript

Objective J

JS2Jack

Source: http://altjs.org

Be JavaScript, my friend

...but it is far from perfect

Macrosultimate flexibility

(ES6 won't have them, btw)

Macros provide a way to extend syntax

Syntax SyntaxMacro

Users can extend the language

It helps evolving the language faster

sweet.jsMacros for JavaScript

sweet.js

Modeled afterScheme macros

Sweet.js

Syntax SyntaxMacro

JS + Macros JSSweet.js

Redefine 'function'

Redefine 'function'

Destructuring

Destructuring

Destructuring

Destructuring

Destructuring

Destructuring

Destructuring

?

?

Nice ranges!

case-style assignment

case-style assignment

Use cases

Try proposed syntax before it makes into the languageCreate Micro-DSLs for your scenarioUse ideas from other languagesMake the new <your-silly-name-here>ScriptImplement basic typesYou get the idea

Start using it now

> npm install sweet.js> sjs -o output.js test_macros.sjs> node output.js

Node.js

Browserhttps://github.com/iammerrick/require-sweet

Questions?

Thanks!

@sergimansillagithub.com/sergi

sergimansilla.com

http://sweetjs.org/https://github.com/mozilla/sweet.jshttp://jlongster.com/why-sweet.js-mattershttp://scriptogr.am/micmath/post/sweet-macros-in-javascripthttps://news.ycombinator.com/item?id=4560691http://youtu.be/_ahvzDzKdB0

References