Revision 1 of 1, by Jwdietrich on 4-15-2020. The page as it is now.

DesignGuidelines

Coding Guidelines for Lazarus

Coding style

Since one style is easier to read, Lazarus follows the CodeGear Coding Style Guide lines. Of course, almost anyone will find some points there, that are arguably less readable than other styles. That's OK, just try to follow at least 90%. See the LCL for examples.
Try to avoid unit cycles (uses section in implementation sections). Reasons: 1. FPC has problems with them. 2. This allows to split units and packages when they have grown big.
Minimize the number of calls from Interfaces to LCL, when performing an action requested by the LCL. The interfaces only notify the LCL, never force something. The LCL decides.
Naming convention: see Nomenclature
All code must work with all checks (range, I/O, overflow, stack) on. Apart from the fact that this helps debugging, some users put these checks into their fpc.cfg, so they are applied to whole Lazarus - including packages and examples.
Names in comments: Comments should help the reader. They are not for the glory of the writer. You can add a name if you are the maintainer aka get the bug reports assigned or if the name is a good search term to find help on this topic.

New files

Every file should start with a header containing the license and a few lines describing the content.
Pascal sources should have lowercase filenames (.pas, .pp, .inc, .lfm, .lrs). You can use CamelCase for unit names.

Include files

Packages

Main Menu Items

The authoritative version can be found in svn. Proposals for improvement can be added to talk page (discussion).