User functions are defined by means of the define statement. The function is defined for all subsequent queries (until it is re-defined). The arguments of the function are given by value: a function may be recurrent.
Prototype:
define function_name [ ( variable_name [ , variable_name ]* ) ] as query
Examples:
define max($a , $b) as if $a > $b then $a else $b; define pi as 3.141592;
User function are called by means of their name (defined with the define operator). The optional arguments are given between parenthesis like built-in functions.
Prototype:
<function name> [ ( <arg1> [ , <argn> ]* ) ]
Examples:
max(12,45) + 1; 46global $r = 11.5;
2 * pi * $r;72.2566