Add guideline: avoid multiple assignments per line

[jferris]

• Reading requires scanning back and forth across the line
• Adding more assignments causes modifications instead of additions
• Hides complexity
• Easy to miss when scanning a method

[sikachu]

hey @jferris, does this covers the following?

breakfast, lunch = :bacon, :hamburger

[gylaz]

+1

[jferris]

@sikachu yes, that's exactly what I'd like to avoid.

[drapergeek]

+1

[croaky]

This could apply to JavaScript, too. Move it to the general "Formatting" section?

[jferris]

I don't feel strongly about this in JavaScript, because the ordering is still sane.

Ruby keeps the variables and values far away from each other:

first, second = 123, 234

JavaScript keeps them together:

var first = 123, second = 234;

Anybody else have thoughts on this?

[drapergeek]

It seems that you used the javascript example in your actual change.

Personally, I don't like it happening in either language but if your problem is with this version:

first, second = 123, 234

then that should probably be the example you use.

[jferris]

@drapergeek yeah, good catch - I pushed a fixed example.

> one, two = 1, 2
=> [1, 2]
> one
=> 1
> two
=> 2

I find that pretty confusing.

[gylaz]

Typo on the first comma.

[drapergeek]

Agreed, I'm still a +1 on this.

[derekprior]

re: JavaScript, for what it's worth: Our guides say use CoffeeScript and the typical way you would do multiple assignment is not supported there. That is, you cannot do x = 1, y =2. You can do the JavaScript 1.7 style "destructuring assignment" though. [a,b] = [1,2]. I don't really think it warrants mentioning.

[mike-burns]

This is still fine, though, right?

> a = [1,2]
> one, two = a
> one
 => 1 
> two
 => 2 

[jferris]

Thanks for all the feedback. I fixed the typo that @gylaz pointed out, squashed, and merged as 754875a.

@mike-burns I'm not sure I've ever seen somebody do exactly that, but I think that would be a separate guideline. Can you link an example of when you'd do assignment from an Array?

[mike-burns]

Sure can't. Don't think I've done this in years.