What rubocop is referring to here is that all ruby blocks evaluate to the
value of the last expression in the block. Rubocop shouldn't complain if
return 'C' if value >= 0
Similarly, your original implementation could be simplified to:
if value >= 0
If you feel that this is more expressive, you might like to know that the
GuardClause cop has a MinBodyLength setting that causes it to trigger only
for more complex methods:
Having a *machine* question about my coding style?
And this, based on someone else's personal opinions of what's
I can certainly see where you're coming from, after all the joy of ruby is
its expressiveness. All I would say is that rubocop is highly configurable,
and is perhaps better suited to group/open source projects, where it helps
to avoid time-wasting arguments over minor style details. It generally
favours more compact code, and personally it has taught me some great
tricks for keeping my code concise. It also identifies some coding idioms
that can hurt application performance.
How do I have to implement the ‘guard clause’ mentioned by Rubocop
I believe you should be able to defuse the complaint by removing the
'return' keyword. Methods as default return the result of the last
instruction executed, so it is sufficient to write
to obtain what you need.
Anyway, it is the first time I hear about this 'rubocop' thing, and it
is nothing I'd like to have to meddle with. Having a *machine*
question about my coding style? And this, based on someone else's
personal opinions of what's better/worse?
Much of Ruby's beauty is due to the variety of possible ways to
express oneself. I happen to use both your original approach and the
suggested one. They both have space, and using both contributes to the
expressivity of your code, as well as to maintain you as a human being
that one small notch above machines.
Subject: Rubocop: Question re. 'Use a guard clause instead of wrapping the code inside a conditional expression.'
Date: mer 02 mar 16 10:24:38 +0100
* Se la Strada e la sua Virtu' non fossero state messe da parte,
* K * Carlo E. Prelz - email@example.com che bisogno ci sarebbe
* di parlare tanto di amore e di rettitudine? (Chuang-Tzu)
Rubocop explains about explicit return at the end of the method. In order
to silence the warning you need to replace `return 'D'` with `'D'`. However
if value >= 0
definitely reads better than the guard clause. If you remove `return`
statements (they are not required) from your initial version the rubocop
doesn't complain. I'd say it's a bug in rubocop. I filed https://github.com/bbatsov/rubocop/issues/2903.
Many thanks again to all of you for your comments; I’ll try to sum this up:
According to Rubocop’s GuardClause Style Cop  it’s better to not wrap all of a method’s code into one conditional; so instead of writing
it’s better style to write
return unless something
As stated by Doug (see above) you can configure the number of lines when to trigger for this Cop ; the default is one.
In my case (conditionally returning different values) there seems to be a bug in Rubocop’s implementation of the GuardClause Style Cop: the GuardClause Style Cop actually shouldn’t be applied here but Rubocop should complain about the unnecessary return statement. Greg was so kind to file an issue .
Ruby allows for many different ways to implement what I’m trying to achieve here, esp. less verbose ways. Which one to pick depends on your personal style.
[…] Having a *machine* question about my coding style? And this, based on someone else’s personal opinions of what’s better/worse?
It depends: it gives me an indication based on the opinions of 231 contributors  who are probably more senior Ruby developers than me. So I see it as a chance to learn and improve – and I’ve got no problem ignoring warnings or switching them off where I don’t agree But this one really bothered me as I couldn’t get my head around the warning.
Much of Ruby’s beauty is due to the variety of possible ways to express oneself. […]
If you remove `return` statements (they are not required) from your initial version the rubocop doesn't complain. I’d say it’s a bug in rubocop.
Then Rubocop’s warning is definitely misleading here; I’m aware of return’s redundancy in Ruby but still like its expressiveness and I did not conclude from the warning re. a guard clause to my redundant use of return!