Naming Conventions

This appendix describes some of the naming conventions I've developed while working on The Castle on Fire. Improvisation and experimentation are encouraged, but you might find these guidelines to be a useful starting point.

Guidelines

Prefer brevity.

The = suffix is for functions/methods which perform an assignment, the ! suffix is for functions/methods which perform any other kind of destructive mutation, and the ? suffix is for boolean variables and for functions/methods which return booleans. For conversions, consider using src->dst for a function or ->dst for a method.

lower-kebab-case is used for local variables, let-fn functions, let-macro macros, built-in functions, built-in macros, class fields, class clauses, and keyword symbols like 'ok. If you're defining a function or macro which is intended to be very global, such as a new control-flow macro or a new numeric function, you should similarly use unprefixed lower-kebab-case.

UpperCamelCase is used for classes, states and RData types. This includes mixins, structs,
local classes defined with let-class, and variables which store classes. Class names should avoid prefixes where possible: Sprite rather than GfxSprite or gfx:Sprite. Capitalization follows the same rules as for a Rust struct, e.g. HudPopup rather than HUDPopup.

An RData's constructor function should be a global variable, named to resemble a class constructor: (Sprite rgb w h), (PhysicsRect coords). If an RData or a class has multiple possible constructors, globally bind a function to the type name, plus a suffix: (Sprite:load path), (TileLayer:from-arr tiles). In general, when manipulating RData and objects, prefer methods over free functions.

Global functions and global variables are categorized into de-facto modules with very short names, like img, phys or res. Global names are prefixed with their "module": img:draw, res:load-resources. Toplevel let variables and let-fn functions are similarly prefixed, mostly to differentiate them from local variables.

(defn phys:step ()
  ...)

(let-fn phys:box-coords (box)
  ...)

A small number of ubiquitous global variables are prefixed with :, purely to make them more brief. For example, :clock for the current game-time, :dt for the "delta time" since the last tick, and :screen-w for the pixel width of the back buffer.