Style Guide and Rule Set Analysis

[akayrak-adesso]

We need to find and compare popular style guides that include lint rule sets used in enterprise projects.

[kaan-unlu]

A style guide from one of the Apple teams is below. It is based on an interview with a developer, so it may not 100% complete, but it is important in terms of having an insight.

NAMING

• Filenames should match with class names.
• Files that contain an additional category / extension for a specific class should have "+" sign (Eg. UIImage+ExampleCategory).
• Do not abbreviate names (files, classes etc. Unless it is an Acronym like URL, HTML).
• Acronyms are always capital (Eg. someHTMLParser).
• While working with frameworks, it is recommended to add framework name abbr. to filenames (Eg. assume there is framework named Device Management, a view controller in that framework can be named as DMSomeViewController. This naming can also be used inside the main app).
• If there is no ambiguity omit types in the naming (Eg. use name = "Kaan" instead of nameString = "Kaan". However type names can be used in some exceptions such as someURLString = "http...").

ORGANIZATION & CODING

• Use doxygen format for documentations.
• The opening curly brackets should be on the same line with the control statement.
• Avoid default case for switch statements.
• It is recommended to divide long control statements into lines (Eg. if xyz == aa && (linebreak) qwe == bb).
• Methods that have a long parameter list can be divided into lines, so that each line has one parameter.
• For an inequality comparison try to use "<" of ">" signs instead of "!=" sign.
• Guard statements should not be a single line statement, there should be a line break after the opening curly brackets like a normal control statements.
• The order inside a file should be like this: 1- Imports 2- Constants 3- Type-definitions (Enum) 4- Interfaces 5- Implementation
• It is recommended to sort imports in alphabetical order.

In addition to the guide above, the development teams in Apple are generally free to use the third party code formatting frameworks such as SwiftLint and the team that I spoke with, mentioned that they use the default styling configuration of SwiftLint.