2.2.2 Infix syntax and function-call syntax

The functions +, -, *, <, >, and = use infix syntax; that is, the function name appears between the arguments to the function. Most other Dylan functions use the function-call syntax shown in the following call to the min function, which returns the smallest of its arguments:

? min(2, 4, 6);
2

The function name appears first, followed by its arguments, which are surrounded by parentheses and separated by commas. Other examples of the function-call syntax follow:

? even?(3);
#f
? zero?(0);
#t

Convention: The names of most predicates end with a question mark — for example, even?, odd?, zero?, positive? and negative?. The question mark is part of the name, and does not have any special behavior. There are exceptions to this convention, such as the predicates named =, <, and >.