The Basis System - Weapons and Complex Integration - Lawrence ...

parameters in parentheses). The number of actual parameters must agree with the number of formal
parameters (possibly zero) declared in the FUNCTION header.
The second way to invoke a function is to use the CALL statement
CALL name actualparams
where name is the function being invoked. actualparams is optional; it can be absent if
name was declared with no parameters, and present (with the same number of parameters) when
name was declared with parameters. Whether or not name returns a value is irrelevant to the
CALL statement, since the value is discarded. Presumably, CALL only makes sense if used with
a function that has side effects, say giving values to global variables, displaying values, or running
physics packages.
If a function has no formal parameters then it can be called in any of the following ways:
CALL name
CALL name()
name()
name
but of these only name() can be used in an expression, and only name or name() return a value.
The meaning of a name is decided at execution time, so it is acceptable to define a function that
calls a second function that has not yet been defined, as long as the second function is defined
before the first function is executed. If this is not done, an error message will be received to the
effect that the name does not exist. A function MAY call itself; logic to prevent infinite recursion
is your responsibility.
22.5 Examples of User Functions
As an example of function definition, the following function computes the square root of its argument
(if real and positive) within a specified tolerance:
FUNCTION myroot (x,eps)
REAL y= 1.,eps1 = max(abs(eps),1.e-12)
IF (x