davideisinger.com

My personal website
Log | Files | Refs | README

index.md (3284B)

      1 ---
      2 title: "CoffeeScript for Ruby Friends"
      3 date: 2010-08-06T00:00:00+00:00
      4 draft: false
      5 canonical_url: https://www.viget.com/articles/coffeescript-for-ruby-friends/
      6 ---
      7 
      8 Hello there, Ruby friend. You've perhaps heard of
      9 [CoffeeScript](https://jashkenas.github.com/coffee-script/),
     10 "JavaScript's less ostentatious kid brother," but it might *as yet* be
     11 unclear why you'd want to stray from Ruby's loving embrace. Well,
     12 friend, I've been playing with it off-and-on for the past few months,
     13 and I've come to the following conclusion: **CoffeeScript combines the
     14 simplicity of Javascript with the elegance of Ruby.**
     15 
     16 ## Syntax
     17 
     18 Despite its compactness as a language, Javascript has always felt a bit
     19 noisy to me. Its excessive punctuation is pretty much the only thing it
     20 has in common with its namesake. CoffeeScript borrows from the syntaxes
     21 of Ruby and Python to create a sort of minimalist Javascript. From
     22 Python, we get significant whitespace and list comprehensions.
     23 
     24 Otherwise, it's all Ruby: semicolons and parentheses around function
     25 arguments are entirely optional. Like Ruby's `||=`, conditional
     26 assignment is handled with `?=`. Conditionals can be inlined
     27 (`something if something_else`). And every statement has an implicit
     28 value, so `return` is unnecessary.
     29 
     30 ## Functions
     31 
     32 Both Javascript and Ruby support functional programming. Ruby offers
     33 numerous language features to make functional programming as concise as
     34 possible, the drawback being the sheer number of ways to define a
     35 function: at least six, by my count (`def`, `do/end`, `{ }`, `lambda`,
     36 `Proc.new`, `proc`).
     37 
     38 At the other extreme, Javascript offers but one way to define a
     39 function: the `function` keyword. It's certainly simple, but especially
     40 in callback-oriented code, you wind up writing `function` one hell of a
     41 lot. CoffeeScript gives us the `->` operator, combining the brevity of
     42 Ruby with the simplicity of Javascript:
     43 
     44 ```coffeescript
     45 thrice: (f) ->
     46   f()
     47   f()
     48   f()
     49 
     50 thrice -> puts "OHAI"
     51 ```
     52 
     53 Which translates to:
     54 
     55 ```javascript
     56 (function(){
     57   var thrice;
     58 
     59   thrice = function(f) {
     60     f();
     61     f();
     62     return f();
     63   };
     64 
     65   thrice(function() { return puts("OHAI"); });
     66 })();
     67 ```
     68 
     69 I'll tell you what that is: MONEY. Money in the BANK.
     70 
     71 ## It's Node
     72 
     73 Though not dependent upon it, CoffeeScript is built to run on top of
     74 [Node.js](http://nodejs.org/). This means you can take advantage of all
     75 the incredible work people are doing with Node, including the
     76 [Express](http://expressjs.com/) web framework, the [Redis Node
     77 Client](https://github.com/fictorial/redis-node-client), and
     78 [Connect](https://github.com/senchalabs/connect), a middleware framework
     79 along the lines of [Rack](http://rack.rubyforge.org/). What's more, its
     80 integration with Node allows you to run CoffeeScript programs from the
     81 command line just like you would Ruby code.
     82 
     83 CoffeeScript is an exciting technology, as both a standalone language
     84 and as a piece of a larger Node.js toolkit. Take a look at
     85 [Defer](http://gfxmonk.net/2010/07/04/defer-taming-asynchronous-javascript-with-coffeescript.html)
     86 to see what the language might soon be capable of, and if you're
     87 participating in this year's [Node.js
     88 Knockout](http://nodeknockout.com/), watch out for the
     89 [Rocketpants](http://nodeknockout.com/teams/2eb41a4c31f50c044a280000).