Ruby Style Guide

Based on Chris Neukirchen's Ruby Style Guide.

Formatting:

• Use UTF-8

• Use 2 space indent, no tabs.

• Use Unix-style line endings.

• Use spaces around operators, after commas, colons and semicolons, around { and before }.

• No spaces after (, [ and before ], ).

• Use one space before statement modifiers (postfix if, unless, while and until).

• Indent when as deep as case.

• Use an empty line before the return value of a method (unless it only has one line), and an empty line between defs.

• Use empty lines to break up a long method into logical paragraphs.

• Keep lines fewer than 80 characters.

• Avoid trailing whitespace.

• Don't align variables/constants assignments or hash keys/values vertically.

Syntax:

• Use def with parentheses when there are arguments.

• Use parentheses for method calls when there are arguments, unless it's part of a DSL.

• Use && and || for boolean expressions.

• Use {...} for single-line blocks and do...end for multi-line blocks.

• Avoid return where not required.

• Avoid using return inside blocks.

• Avoid line continuation (\) where not required.

• Avoid using the return value of = in comparisons.

• Use ||= freely.

• Avoid the and and or operators.

Naming:

• Use snake_case for methods.

• Use CamelCase for classes and modules. (Keep acronyms like HTTP, RFC, XML uppercase.)

• Use SCREAMING_SNAKE_CASE for other constants.

• Use _ or names prefixed with _ for unused or private variables.

• When defining binary operators, name the argument "other".

Comments:

• Comments longer than a word are capitalized and use punctuation.

• Avoid superfluous comments.

The rest:

• Avoid writing methods that span more than 10 lines.

• Avoid writing methods that receive more than 3 parameters.

• Use def self.method to define singleton methods.

• Avoid needless metaprogramming.

• Don't use rescue as a predicate.

• Don't use catch-all rescue.

• Don't use case without an else branch.

• Use the hashrocket notation (=>) to build a literal Hash.

• Use doublequotes for one-line strings.

General:

• Code in a functional way, avoid mutation when it makes sense.

• Do not mutate arguments unless that is the purpose of the method.

• Do not mess around in core classes when writing libraries.

• Do not program defensively.

• Keep the code simple.

• Don't overdesign.

• Don't underdesign.

• Avoid bugs.

• Read other style guides and apply the parts that don't dissent with this list.

• Be consistent.

• Use common sense.