Naming Conventions

Several conventions for naming module bindings help programmers identify the purposes of bindings. In general, the names of bindings do not affect the semantics of a program, but are simply used to improve readability. (The exceptions to this rule are the -definer suffix used by definition macros, and the -setter suffix, described later in this section.)

Module bindings used to hold types begin and end with angle brackets.

<window>
<object>
<character>
<number>
<stream>
<list>

Variable module bindings begin and end with asterisks.

*parse-level*
*incremental-search-string*
*machine-state*
*window-count*

Program constants begin with a dollar sign.

$pi
$end-of-file

The names of most predicate functions end with a question mark. Predicates are functions that return a true or false value.

subclass?	
even?
instance?

Operations that return a value similar to one of their arguments and that also destructively modify the argument end in a !. (It will often also be the case that destructive and non-destructive variations of the function exist.) ! isn't a universal warning that an operation is destructive. Destructive functions that return other values (like -setter functions and pop) don't need to use the ! convention.

reverse!
sort!

Operations that retrieve a value from a location are called getters. Operations that store into a location are called setters. In general, getters and setters come in pairs. Setter binding names are derived by appending -setter to the corresponding getter binding name. This convention is used to generate setter names automatically, and it is used by :=, the assignment operator, to find the setter that corresponds to a given getter.

element      element-setter
size         size-setter
color        color-setter