gurkendoktor on Github Ruby Styleguide

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gurkendoktor 13y

&&/|| can bite you just as well:

if first_user = User.find(4) && second_user = User.find(6) ... end

rauljara 13y

I may be missing something obvious here. How would this code bite you?

alanctgardner2 13y

> first_user = User.find(4) && second_user = User.find(6)

It looks like it would evaluate as: first_user = (User.find(4) and second_user = User.find(6))

That is to say, the assignment comes after the boolean operation, which is unexpected.

pooriaazimi 13y

Well, I expect

    first_user = User.find(4) && second_user = User.find(6)

to be literally equivalent to

    second_user = User.find(6)
    first_user = User.find(4) && second_user

I honestly can't see why you might want it to mean something else...

Edit: I see. if you do something like

    if (first_user = User.find(4) && second_user = User.find(6)) {
      ..
    }

it might bite you. You might expect it to be equivalent to

    first_user = User.find(4)
    second_user = User.find(6)
    if (first_user && second_user) {
      ..
    }

which I personally think is a very, very bad practice. Parenthesis should always be used when there's even the slightest possibility that you or another maintainer/contributor might be confused about.

alanctgardner2 13y

Personally, I'm almost painfully verbose with my parens to avoid exactly this scenario. Better to be explicit about my intent to the interpreter and other coders.

Having an assignment that could be skipped by short-circuiting also seems like bad practice, but I realize it was designed to be a toy example

gurkendoktor 13y

Skipping the second assignment if I don't need it is more of an optimisation. The "long form" would be,

first_user = User.find(4) if first_user second_user = User.find(6) if second_user ... end end

gurkendoktor 13y

> Parenthesis should always be used when there's even the slightest possibility that you or another maintainer/contributor might be confused about.

Yes, but you can make the same point in favor of using "and" and "or" (and deprecating &&/||).

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