72 lines
3.2 KiB
Markdown
72 lines
3.2 KiB
Markdown
---
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title: "CoffeeScript for Ruby Bros"
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date: 2010-08-06T00:00:00+00:00
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draft: false
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needs_review: true
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canonical_url: https://www.viget.com/articles/coffeescript-for-ruby-bros/
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---
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Hello there, Ruby friend. You've perhaps heard of
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[CoffeeScript](https://jashkenas.github.com/coffee-script/),
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"JavaScript's less ostentatious kid brother," but it might *as yet* be
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unclear why you'd want to stray from Ruby's loving embrace. Well,
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friend, I've been playing with it off-and-on for the past few months,
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and I've come to the following conclusion: **CoffeeScript combines the
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simplicity of Javascript with the elegance of Ruby.**
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## Syntax
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Despite its compactness as a language, Javascript has always felt a bit
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noisy to me. Its excessive punctuation is pretty much the only thing it
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has in common with its namesake. CoffeeScript borrows from the syntaxes
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of Ruby and Python to create a sort of minimalist Javascript. From
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Python, we get significant whitespace and list comprehensions.
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Otherwise, it's all Ruby: semicolons and parentheses around function
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arguments are entirely optional. Like Ruby's `||=`, conditional
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assignment is handled with `?=`. Conditionals can be inlined
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(`something if something_else`). And every statement has an implicit
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value, so `return` is unnecessary.
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## Functions
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Both Javascript and Ruby support functional programming. Ruby offers
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numerous language features to make functional programming as concise as
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possible, the drawback being the sheer number of ways to define a
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function: at least six, by my count (`def`, `do/end`, `{ }`, `lambda`,
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`Proc.new`, `proc`).
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At the other extreme, Javascript offers but one way to define a
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function: the `function` keyword. It's certainly simple, but especially
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in callback-oriented code, you wind up writing `function` one hell of a
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lot. CoffeeScript gives us the `->` operator, combining the brevity of
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Ruby with the simplicity of Javascript:
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thrice: (f) -> f() f() f() thrice -> puts "OHAI"
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Which translates to:
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(function(){ var thrice; thrice = function(f) { f(); f(); return f(); }; thrice(function() { return puts("OHAI"); }); })();
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I'll tell you what that is: MONEY. Money in the BANK.
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## It's Node
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Though not dependent upon it, CoffeeScript is built to run on top of
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[Node.js](http://nodejs.org/). This means you can take advantage of all
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the incredible work people are doing with Node, including the
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[Express](http://expressjs.com/) web framework, the [Redis Node
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Client](https://github.com/fictorial/redis-node-client), and
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[Connect](https://github.com/senchalabs/connect), a middleware framework
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along the lines of [Rack](http://rack.rubyforge.org/). What's more, its
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integration with Node allows you to run CoffeeScript programs from the
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command line just like you would Ruby code.
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CoffeeScript is an exciting technology, as both a standalone language
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and as a piece of a larger Node.js toolkit. Take a look at
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[Defer](http://gfxmonk.net/2010/07/04/defer-taming-asynchronous-javascript-with-coffeescript.html)
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to see what the language might soon be capable of, and if you're
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participating in this year's [Node.js
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Knockout](http://nodeknockout.com/), watch out for the
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[Rocketpants](http://nodeknockout.com/teams/2eb41a4c31f50c044a280000).
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