2.4 Function Descriptions

Each function is provided with a prototypical header line. Each formal parameter is given a name and suffixed with its allowed type. Lower case, italic tokens are names of classes and upper case, bold face, tokens are parameter names referred to in the definition. The type of the value returned by the function (if any) is suffixed to the parameter list. If it is not commonly used the parameter type may be a specific set enclosed in brackets {…}. For example:

PUTD(FNAME:id, TYPE:ftype, BODY:{lambda, function-pointer}):id

PUTD is a function with three parameters. The parameter FNAME is an id to be the name of the function being defined. TYPE is the type of the function being defined and BODY is a lambda expression or a function-pointer. PUTD returns the name of the function being defined.

Functions which accept formal parameter lists of arbitrary length have the type class and parameter enclosed in square brackets indicating that zero or more occurrences of that argument are permitted. For example:

AND([U:any]):extra-boolean

AND is a function which accepts zero or more arguments which may be of any type.