Style Guide
Software running on RISC OS computers should, wherever possible, maintain a consistent look and feel. This makes it easier for a user accustomed to how one application works to quickly and intuitively learn the basics of how to use another, as similar controls look and behave in a similar manner.
To this end there is a Style Guide, the first edition of which was published by Acorn in paper form and supplied with the RISC OS 3 Programmers Reference Manuals in 1993, and later (unchanged) in PDF format as part of the C/C++ Suite from Castle Technology Ltd,.
RISC OS Open Ltd edited a third edition and published it in 2015 with ISBN 978-0-9931948-0-1. Among many improvements based on developments within RISC OS and in the developer community is some coverage of Unicode support via the UTF-8 alphabet in RISC OS 5.