Style Guide

This document describes the conventions adopted in Ledger for the relevant languages: English and C++.


This section applies to written communication in docs, code comments, commit messages, emails, etc.

ledger vs Ledger vs the ledger vs ...

The project and the resulting application are called “Ledger”. It is a proper name, hence it is not preceded by an article.

Do: Ledger synchronizes user data across devices

Don't: the Ledger synchronizes user data across devices

Don't: ledger synchronizes user data across devices

All of the data stored in Ledger on behalf of a user is sometimes referred to as this user's ledger. In that case “ledger” is a common name - not capitalized and preceded by an article.

Do: each user has a separate ledger

Don't: each user has separate Ledger


Ledger, like the rest of Fuchsia, follows Google C++ Style Guide. In a few cases not covered there, we choose a convention.

Naming of callback parameters

If there is a need to distinguish callback parameters of a method or a class, call them on_<event>.

Do: fit::function<void(int)> on_done

Don't: fit::function<void(int)> done_callback

Usage of fxl::StringView vs std::string

This section discusses which string types to use for C++ API arguments.

Use a fxl::StringView (non-ref) if the functionality just reads the string: fxl::StringView can handle any stream of bytes without copies.

Use a std::string (non-ref) if:

  • the functionality needs to take ownership of the string (it allows users of the functionality to std::move the string if they don't reuse it afterwards), or
  • you need to pass the string over to a function that requires an std::string.

You might want to use a const std:string& (const ref), if you need to call a function that itself takes a const std:string& (and you cannot or don't want to change it to take an fxl::StringView).