Name: ruby-style-guide
Owner: Simpleweb
Description: A community-driven Ruby coding style guide
Created: 2012-11-14 09:51:56.0
Updated: 2013-01-13 03:40:34.0
Pushed: 2012-10-18 07:00:45.0
Size: 151
Language: Ruby
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Style is what separates the good from the great.
– Bozhidar Batsov
One thing has always bothered me as Ruby developer - Python developers have a great programming style reference (PEP-8) and we never got an official guide, documenting Ruby coding style and best practices. And I do believe that style matters. I also believe that such fine fellows, like us Ruby developers, should be quite capable to produce this coveted document.
This guide started its life as our internal company Ruby coding guidelines (written by yours truly). At some point I decided that the work I was doing might be interesting to members of the Ruby community in general and that the world had little need for another internal company guideline. But the world could certainly benefit from a community-driven and community-sanctioned set of practices, idioms and style prescriptions for Ruby programming.
Since the inception of the guide I've received a lot of feedback from members of the exceptional Ruby community around the world. Thanks for all the suggestions and the support! Together we can make a resource beneficial to each and every Ruby developer out there.
By the way, if you're into Rails you might want to check out the complementary Ruby on Rails 3 Style Guide.
This Ruby style guide recommends best practices so that real-world Ruby programmers can write code that can be maintained by other real-world Ruby programmers. A style guide that reflects real-world usage gets used, and a style guide that holds to an ideal that has been rejected by the people it is supposed to help risks not getting used at all – no matter how good it is.
The guide is separated into several sections of related rules. I've tried to add the rationale behind the rules (if it's omitted I've assumed that is pretty obvious).
I didn't come up with all the rules out of nowhere - they are mostly based on my extensive career as a professional software engineer, feedback and suggestions from members of the Ruby community and various highly regarded Ruby programming resources, such as “Programming Ruby 1.9” and “The Ruby Programming Language”.
The guide is still a work in progress - some rules are lacking examples, some rules don't have examples that illustrate them clearly enough. In due time these issues will be addressed - just keep them in mind for now.
You can generate a PDF or an HTML copy of this guide using Transmuter.
Nearly everybody is convinced that every style but their own is ugly and unreadable. Leave out the “but their own” and they're probably right…
– Jerry Coffin (on indentation)
Use UTF-8 as the source file encoding.
Use two spaces per indentation level. No hard tabs.
od
some_method
_something
d - four spaces
some_method
do_something
Use Unix-style line endings. (*BSD/Solaris/Linux/OSX users are covered by default, Windows users have to be extra careful.)
If you're using Git you might want to add the following configuration setting to protect your project from Windows line endings creeping in:
$ git config –global core.autocrlf true
Use spaces around operators, after commas, colons and semicolons, around {
and before }. Whitespace might be (mostly) irrelevant to the Ruby
interpreter, but its proper use is the key to writing easily
readable code.
= 1 + 2
= 1, 2
2 ? true : false; puts 'Hi'
2, 3].each { |e| puts e }
The only exception is when using the exponent operator:
d
M * c ** 2
od
M * c**2
No spaces after (, [ or before ], ).
(arg).other
2, 3].length
Indent when as deep as case. I know that many would disagree
with this one, but it's the style established in both the “The Ruby
Programming Language” and “Programming Ruby”.
song.name == 'Misty'
ts 'Not again!'
song.duration > 120
ts 'Too long!'
Time.now.hour > 21
ts "It's too late"
ng.play
= case year
when 1850..1889 then 'Blues'
when 1890..1909 then 'Ragtime'
when 1910..1929 then 'New Orleans Jazz'
when 1930..1939 then 'Swing'
when 1940..1950 then 'Bebop'
else 'Jazz'
end
Use empty lines between defs and to break up a method into logical
paragraphs.
some_method
ta = initialize(options)
ta.manipulate!
ta.result
some_method
sult
Align the parameters of a method call if they span over multiple lines.
arting point (line is too long)
send_mail(source)
iler.deliver(to: 'bob@example.com', from: 'us@example.com', subject: 'Important message', body: source.text)
d (normal indent)
send_mail(source)
iler.deliver(
to: 'bob@example.com',
from: 'us@example.com',
subject: 'Important message',
body: source.text)
d (double indent)
send_mail(source)
iler.deliver(
to: 'bob@example.com',
from: 'us@example.com',
subject: 'Important message',
body: source.text)
od
send_mail(source)
iler.deliver(to: 'bob@example.com',
from: 'us@example.com',
subject: 'Important message',
body: source.text)
Use RDoc and its conventions for API documentation. Don't put an
empty line between the comment block and the def.
Keep lines fewer than 80 characters.
Avoid trailing whitespace.
Use def with parentheses when there are arguments. Omit the
parentheses when the method doesn't accept any arguments.
some_method
body omitted
some_method_with_arguments(arg1, arg2)
body omitted
Never use for, unless you know exactly why. Most of the time iterators
should be used instead. for is implemented in terms of each (so
you're adding a level of indirection), but with a twist - for
doesn't introduce a new scope (unlike each) and variables defined
in its block will be visible outside it.
= [1, 2, 3]
d
elem in arr do
ts elem
od
each { |elem| puts elem }
Never use then for multi-line if/unless.
d
ome_condition then
body omitted
od
ome_condition
body omitted
Favor the ternary operator(?:) over if/then/else/end constructs.
It's more common and obviously more concise.
d
lt = if some_condition then something else something_else end
od
lt = some_condition ? something : something_else
Use one expression per branch in a ternary operator. This
also means that ternary operators must not be nested. Prefer
if/else constructs in these cases.
d
_condition ? (nested_condition ? nested_something : nested_something_else) : something_else
od
ome_condition
sted_condition ? nested_something : nested_something_else
mething_else
Never use if x: ... - it is removed in Ruby 1.9. Use
the ternary operator instead.
d
lt = if some_condition: something else something_else end
od
lt = some_condition ? something : something_else
Never use if x; .... Use the ternary operator instead.
Use when x then ... for one-line cases. The alternative syntax
when x: ... is removed in Ruby 1.9.
Never use when x; .... See the previous rule.
Use &&/|| for boolean expressions, and/or for control flow. (Rule
of thumb: If you have to use outer parentheses, you are using the
wrong operators.)
olean expression
ome_condition && some_other_condition
_something
ntrol flow
ment.saved? or document.save!
Avoid multi-line ?: (the ternary operator); use if/unless instead.
Favor modifier if/unless usage when you have a single-line
body. Another good alternative is the usage of control flow and/or.
d
ome_condition
_something
od
omething if some_condition
other good option
_condition and do_something
Favor unless over if for negative conditions (or control
flow or).
d
omething if !some_condition
od
omething unless some_condition
other good option
_condition or do_something
Never use unless with else. Rewrite these with the positive case first.
d
ss success?
ts 'failure'
ts 'success'
od
uccess?
ts 'success'
ts 'failure'
Don't use parentheses around the condition of an if/unless/while,
unless the condition contains an assignment (see “Using the return
value of =” below).
d
x > 10)
body omitted
od
> 10
body omitted
x = self.next_value)
body omitted
Favor modifier while/until usage when you have a single-line
body.
d
e some_condition
_something
od
omething while some_condition
Favor until over while for negative conditions.
d
omething while !some_condition
od
omething until some_condition
Omit parentheses around parameters for methods that are part of an
internal DSL (e.g. Rake, Rails, RSpec), methods that are with
“keyword” status in Ruby (e.g. attr_reader, puts) and attribute
access methods. Use parentheses around the arguments of all other
method invocations.
s Person
tr_reader :name, :age
omitted
erance = Person.new('Temperance', 30)
erance.name
temperance.age
Math.sin(y)
y.delete(e)
Prefer {...} over do...end for single-line blocks. Avoid using
{...} for multi-line blocks (multiline chaining is always
ugly). Always use do...end for “control flow” and “method
definitions” (e.g. in Rakefiles and certain DSLs). Avoid do...end
when chaining.
s = ['Bozhidar', 'Steve', 'Sarah']
od
s.each { |name| puts name }
d
s.each do |name|
ts name
od
s.select { |name| name.start_with?('S') }.map { |name| name.upcase }
d
s.select do |name|
me.start_with?('S')
map { |name| name.upcase }
Some will argue that multiline chaining would look OK with the use of {…}, but they should ask themselves - is this code really readable and can't the blocks contents be extracted into nifty methods?
Avoid return where not required for flow of control.
d
some_method(some_arr)
turn some_arr.size
od
some_method(some_arr)
me_arr.size
Avoid self where not required. (It is only required when calling a self write accessor.)
d
ready?
self.last_reviewed_at > self.last_updated_at
self.worker.update(self.content, self.options)
self.status = :in_progress
d
lf.status == :verified
od
ready?
last_reviewed_at > last_updated_at
worker.update(content, options)
self.status = :in_progress
d
atus == :verified
As a corollary, avoid shadowing methods with local variables unless they are both equivalent.
s Foo
tr_accessor :options
ok
f initialize(options)
self.options = options
# both options and self.options are equivalent here
d
bad
f do_something(options = {})
unless options[:when] == :later
output(self.options[:message])
end
d
good
f do_something(params = {})
unless params[:when] == :later
output(options[:message])
end
d
Use spaces around the = operator when assigning default values to method parameters:
d
some_method(arg1=:default, arg2=nil, arg3=[])
do something...
od
some_method(arg1 = :default, arg2 = nil, arg3 = [])
do something...
While several Ruby books suggest the first style, the second is much more prominent in practice (and arguably a bit more readable).
Avoid line continuation (\) where not required. In practice, avoid using line continuations at all.
d
lt = 1 - \
2
od (but still ugly as hell)
lt = 1 \
- 2
Using the return value of = (an assignment) is ok, but surround the
assignment with parentheses.
od - shows intended use of assignment
v = array.grep(/foo/)) ...
d
= array.grep(/foo/) ...
so good - shows intended use of assignment and has correct precedence.
v = self.next_value) == 'hello' ...
Use ||= freely to initialize variables.
t name to Bozhidar, only if it's nil or false
||= 'Bozhidar'
Don't use ||= to initialize boolean variables. (Consider what
would happen if the current value happened to be false.)
d - would set enabled to true even if it was false
led ||= true
od
led = true if enabled.nil?
Avoid using Perl-style special variables (like $0-9, $`,
etc. ). They are quite cryptic and their use in anything but
one-liner scripts is discouraged.
Never put a space between a method name and the opening parenthesis.
d
+ 2) + 1
od
+ 2) + 1
If the first argument to a method begins with an open parenthesis,
always use parentheses in the method invocation. For example, write
f((3 + 2) + 1).
Always run the Ruby interpreter with the -w option so it will warn
you if you forget either of the rules above!
The new hash literal syntax is preferred in Ruby 1.9 when your hash keys are symbols.
d
= { :one => 1, :two => 2 }
od
= { one: 1, two: 2 }
The new lambda literal syntax is preferred in Ruby 1.9.
d
da = lambda { |a, b| a + b }
da.call(1, 2)
od
da = ->(a, b) { a + b }
da.(1, 2)
Use _ for unused block parameters.
d
lt = hash.map { |k, v| v + 1 }
od
lt = hash.map { |_, v| v + 1 }
The only real difficulties in programming are cache invalidation and naming things.
– Phil Karlton
Use snake_case for methods and variables.
Use CamelCase for classes and modules. (Keep acronyms like HTTP,
RFC, XML uppercase.)
Use SCREAMING_SNAKE_CASE for other constants.
The names of predicate methods (methods that return a boolean value)
should end in a question mark.
(i.e. Array#empty?).
The names of potentially “dangerous” methods (i.e. methods that modify self or the
arguments, exit! (doesn't run the finalizers like exit does), etc.) should end with an exclamation mark if
there exists a safe version of that dangerous method.
d - there is not matching 'safe' method
s Person
f update!
d
od
s Person
f update
d
od
s Person
f update!
d
f update
d
Define the non-bang (safe) method in terms of the bang (dangerous) one if possible.
s Array
f flatten_once!
res = []
each do |e|
[*e].each { |f| res << f }
end
replace(res)
d
f flatten_once
dup.flatten_once!
d
When using reduce with short blocks, name the arguments |a, e|
(accumulator, element).
When defining binary operators, name the argument other.
+(other)
body omitted
Prefer map over collect, find over detect, select over
find_all, reduce over inject and size over length. This is
not a hard requirement; if the use of the alias enhances
readability, it's ok to use it. The rhyming methods are inherited from
Smalltalk and are not common in other programming languages. The
reason the use of select is encouraged over find_all is that it
goes together nicely with reject and its name is pretty self-explanatory.
Good code is its own best documentation. As you're about to add a comment, ask yourself, “How can I improve the code so that this comment isn't needed?” Improve the code and then document it to make it even clearer.
– Steve McConnell
Write self-documenting code and ignore the rest of this section. Seriously!
Comments longer than a word are capitalized and use punctuation. Use one space after periods.
Avoid superfluous comments.
d
ter += 1 # increments counter by one
Keep existing comments up-to-date. An outdated is worse than no comment at all.
Good code is like a good joke - it needs no explanation.
– Russ Olsen
Annotations should usually be written on the line immediately above the relevant code.
The annotation keyword is followed by a colon and a space, then a note describing the problem.
If multiple lines are required to describe the problem, subsequent
lines should be indented two spaces after the #.
bar
FIXME: This has crashed occasionally since v3.2.1. It may
be related to the BarBazUtil upgrade.
z(:quux)
In cases where the problem is so obvious that any documentation would be redundant, annotations may be left at the end of the offending line with no note. This usage should be the exception and not the rule.
bar
eep 100 # OPTIMIZE
Use TODO to note missing features or functionality that should be
added at a later date.
Use FIXME to note broken code that needs to be fixed.
Use OPTIMIZE to note slow or inefficient code that may cause
performance problems.
Use HACK to note code smells where questionable coding practices
were used and should be refactored away.
Use REVIEW to note anything that should be looked at to confirm it
is working as intended. For example: REVIEW: Are we sure this is how the
client does X currently?
Use other custom annotation keywords if it feels appropriate, but be
sure to document them in your project's README or similar.
When designing class hierarchies make sure that they conform to the Liskov Substitution Principle.
Try to make your classes as [SOLID](http://en.wikipedia.org/wiki/SOLID_(object-oriented_design)) as possible.
Always supply a proper to_s method for classes that represent
domain objects.
s Person
tr_reader :first_name, :last_name
f initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
d
f to_s
"#@first_name #@last_name"
d
Use the attr family of functions to define trivial accessors or
mutators.
d
s Person
f initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
d
f first_name
@first_name
d
f last_name
@last_name
d
od
s Person
tr_reader :first_name, :last_name
f initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
d
Consider using Struct.new, which defines the trivial accessors,
constructor and comparison operators for you.
od
s Person
tr_reader :first_name, :last_name
f initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
d
tter
s Person < Struct.new(:first_name, :last_name)
Consider adding factory methods to provide additional sensible ways to create instances of a particular class.
s Person
f self.create(options_hash)
# body omitted
d
Prefer duck-typing over inheritance.
d
s Animal
abstract method
f speak
d
tend superclass
s Duck < Animal
f speak
puts 'Quack! Quack'
d
tend superclass
s Dog < Animal
f speak
puts 'Bau! Bau!'
d
od
s Duck
f speak
puts 'Quack! Quack'
d
s Dog
f speak
puts 'Bau! Bau!'
d
Avoid the usage of class (@@) variables due to their “nasty” behavior
in inheritance.
s Parent
class_var = 'parent'
f self.print_class_var
puts @@class_var
d
s Child < Parent
class_var = 'child'
nt.print_class_var # => will print "child"
As you can see all the classes in a class hierarchy actually share one class variable. Class instance variables should usually be preferred over class variables.
Assign proper visibility levels to methods (private, protected)
in accordance with their intended usage. Don't go off leaving
everything public (which is the default). After all we're coding
in Ruby now, not in Python.
Indent the public, protected, and private methods as much the
method definitions they apply to. Leave one blank line above them.
s SomeClass
f public_method
# ...
d
ivate
f private_method
# ...
d
Use def self.method to define singleton methods. This makes the code
easier to refactor since the class name is not repeated.
s TestClass
bad
f TestClass.some_method
# body omitted
d
good
f self.some_other_method
# body omitted
d
Also possible and convenient when you
have to define many singleton methods.
ass << self
def first_method
# body omitted
end
def second_method_etc
# body omitted
end
d
Signal exceptions using the fail keyword. Use raise only when
catching an exception and re-raising it (because here you're not failing, but explicitly and purposefully raising an exception).
n
il 'Oops';
ue => error
ise if error.message != 'Oops'
Never return from an ensure block. If you explicitly return from a
method inside an ensure block, the return will take precedence over
any exception being raised, and the method will return as if no
exception had been raised at all. In effect, the exception will be
silently thrown away.
foo
gin
fail
sure
return 'very bad idea'
d
Use implicit begin blocks when possible.
d
foo
gin
# main logic goes here
scue
# failure handling goes here
d
od
foo
main logic goes here
ue
failure handling goes here
Mitigate the proliferation of begin blocks by using
contingency methods (a term coined by Avdi Grimm).
d
n
mething_that_might_fail
ue IOError
handle IOError
n
mething_else_that_might_fail
ue IOError
handle IOError
od
with_io_error_handling
ield
ue IOError
handle IOError
_io_error_handling { something_that_might_fail }
_io_error_handling { something_else_that_might_fail }
Don't suppress exceptions.
d
n
an exception occurs here
ue SomeError
the rescue clause does absolutely nothing
d
omething rescue nil
Don't use exceptions for flow of control.
d
n
/ d
ue ZeroDivisionError
ts 'Cannot divide by 0!'
od
.zero?
ts 'Cannot divide by 0!'
/ d
Avoid rescuing the Exception class. This will trap signals and calls to
exit, requiring you to kill -9 the process.
d
n
calls to exit and kill signals will be caught (except kill -9)
it
ue Exception
ts "you didn't really want to exit, right?"
exception handling
od
n
a blind rescue rescues from StandardError, not Exception as many
programmers assume.
ue => e
exception handling
so good
n
an exception occurs here
ue StandardError => e
exception handling
Put more specific exceptions higher up the rescue chain, otherwise they'll never be rescued from.
d
n
some code
ue Exception => e
some handling
ue StandardError => e
some handling
od
n
some code
ue StandardError => e
some handling
ue Exception => e
some handling
Release external resources obtained by your program in an ensure block.
File.open('testfile')
n
.. process
ue
.. handle error
re
close unless f.nil?
Favor the use of exceptions for the standard library over introducing new exception classes.
Prefer literal array and hash creation notation (unless you need to pass parameters to their constructors, that is).
d
= Array.new
= Hash.new
od
= []
= {}
Prefer %w to the literal array syntax when you need an array of
strings.
d
ES = ['draft', 'open', 'closed']
od
ES = %w(draft open closed)
Avoid the creation of huge gaps in arrays.
= []
100] = 1 # now you have an array with lots of nils
Use Set instead of Array when dealing with unique elements. Set
implements a collection of unordered values with no duplicates. This
is a hybrid of Array's intuitive inter-operation facilities and
Hash's fast lookup.
Prefer symbols instead of strings as hash keys.
d
= { 'one' => 1, 'two' => 2, 'three' => 3 }
od
= { one: 1, two: 2, three: 3 }
Avoid the use of mutable objects as hash keys.
The new hash literal syntax is preferred in Ruby 1.9 when your hash keys are symbols.
d
= { :one => 1, :two => 2, :three => 3 }
od
= { one: 1, two: 2, three: 3 }
Rely on the fact that hashes in Ruby 1.9 are ordered.
Never modify a collection while traversing it.
Prefer string interpolation instead of string concatenation:
d
l_with_name = user.name + ' <' + user.email + '>'
od
l_with_name = "#{user.name} <#{user.email}>"
Consider padding string interpolation code with space. It more clearly sets the code apart from the string.
user.last_name }, #{ user.first_name }"
Prefer single-quoted strings when you don't need string interpolation or
special symbols such as \t, \n, ', etc.
d
= "Bozhidar"
od
= 'Bozhidar'
Don't use {} around instance variables being interpolated into a
string.
s Person
tr_reader :first_name, :last_name
f initialize(first_name, last_name)
@first_name = first_name
@last_name = last_name
d
bad
f to_s
"#{@first_name} #{@last_name}"
d
good
f to_s
"#@first_name #@last_name"
d
Avoid using String#+ when you need to construct large data chunks.
Instead, use String#<<. Concatenation mutates the string instance in-place
and is always faster than String#+, which creates a bunch of new string objects.
od and also fast
= ''
<< '<h1>Page title</h1>'
graphs.each do |paragraph|
ml << "<p>#{paragraph}</p>"
Don't use regular expressions if you just need plain text search in string:
string['text']
For simple constructions you can use regexp directly through string index.
h = string[/regexp/] # get content of matched regexp
t_group = string[/text(grp)/, 1] # get content of captured group
ng[/text (grp)/, 1] = 'replace' # string => 'text replace'
Use non-capturing groups when you don't use captured result of parentheses.
rst|second)/ # bad
first|second)/ # good
Avoid using $1-9 as it can be hard to track what they contain. Named groups can be used instead.
d
gexp)/ =~ string
ess $1
od
meaningful_var>regexp)/ =~ string
ess meaningful_var
Character classes have only few special characters you should care about:
^, -, \, ], so don't escape . or brackets in [].
Be careful with ^ and $ as they match start/end of line, not string endings.
If you want to match the whole string use: \A and \z (not to be
confused with \Z which is the equivalent of /\n?\z/).
ng = "some injection\nusername"
ng[/^username$/] # matches
ng[/\Ausername\z/] # don't match
Use x modifier for complex regexps. This makes them more readable and you
can add some useful comments. Just be careful as spaces are ignored.
xp = %r{
art # some text
# white space char
roup) # first group
:alt1|alt2) # some alternation
d
For complex replacements sub/gsub can be used with block or hash.
Use %w freely.
ES = %w(draft open closed)
Use %() for single-line strings which require both interpolation
and embedded double-quotes. For multi-line strings, prefer heredocs.
d (no interpolation needed)
iv class="text">Some text</div>)
ould be '<div class="text">Some text</div>'
d (no double-quotes)
is is #{quality} style)
ould be "This is #{quality} style"
d (multiple lines)
iv>\n<span class="big">#{exclamation}</span>\n</div>)
ould be a heredoc.
od (requires interpolation, has quotes, single line)
r><td class="name">#{name}</td>)
Use %r only for regular expressions matching more than one '/' character.
d
s+)
ill bad
/(.*)$)
ould be /^\/(.*)$/
od
/blog/2011/(.*)$)
Avoid %q, %Q, %x, %s, and %W.
Prefer () as delimiters for all % literals.
Avoid needless metaprogramming.
Do not mess around in core classes when writing libraries. (Do not monkey patch them.)
The block form of class_eval is preferable to the string-interpolated form.
when you use the string-interpolated form, always supply __FILE__ and __LINE__, so that your backtraces make sense:
s_eval 'def use_relative_model_naming?; true; end', __FILE__, __LINE__
define_method is preferable to class_eval{ def ... }
When using class_eval (or other eval) with string interpolation, add a comment block showing its appearance if interpolated (a practice I learned from the rails code):
om activesupport/lib/active_support/core_ext/string/output_safety.rb
FE_STRING_METHODS.each do |unsafe_method|
'String'.respond_to?(unsafe_method)
class_eval <<-EOT, __FILE__, __LINE__ + 1
def #{unsafe_method}(*args, &block) # def capitalize(*args, &block)
to_str.#{unsafe_method}(*args, &block) # to_str.capitalize(*args, &block)
end # end
def #{unsafe_method}!(*args) # def capitalize!(*args)
@dirty = true # @dirty = true
super # super
end # end
EOT
d
avoid using method_missing for metaprogramming. Backtraces become messy; the behavior is not listed in #methods; misspelled method calls might silently work (nukes.launch_state = false). Consider using delegation, proxy, or define_method instead. If you must, use method_missing,
be sure to also define respond_to_missing?
only catch methods with a well-defined prefix, such as find_by_* – make your code as assertive as possible.
call super at the end of your statement
delegate to assertive, non-magical methods:
d
method_missing?(meth, *args, &block)
/^find_by_(?<prop>.*)/ =~ meth
# ... lots of code to do a find_by
se
super
d
od
method_missing?(meth, *args, &block)
/^find_by_(?<prop>.*)/ =~ meth
find_by(prop, *args, &block)
se
super
d
st of all, though, would to define_method as each findable attribute is declared
Write ruby -w safe code.
Avoid hashes as optional parameters. Does the method do too much?
Avoid methods longer than 10 LOC (lines of code). Ideally, most methods will be shorter than 5 LOC. Empty lines do not contribute to the relevant LOC.
Avoid parameter lists longer than three or four parameters.
If you really have to, add “global” methods to Kernel and make them private.
Use class instance variables instead of global variables.
_bar = 1
d
s Foo
ass << self
attr_accessor :bar
d
bar = 1
Avoid alias when alias_method will do.
Use OptionParser for parsing complex command line options and
ruby -s for trivial command line options.
Code in a functional way, avoiding mutation when that makes sense.
Do not mutate arguments unless that is the purpose of the method.
Avoid more than three levels of block nesting.
Be consistent. In an ideal world, be consistent with these guidelines.
Use common sense.
Nothing written in this guide is set in stone. It's my desire to work together with everyone interested in Ruby coding style, so that we could ultimately create a resource that will be beneficial to the entire Ruby community.
Feel free to open tickets or send pull requests with improvements. Thanks in advance for your help!
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