HP 3000 Manuals HP 3000 Manuals
DEF FN
The DEF FN statement defines the beginning of a multi-line function. It
is not executable.
Syntax
Numeric function:
DEF [type] FNidentifier [(f_param[,f_param]...)]
String function:
DEF FNidentifier$ [(f_param[,f_param]...)]
Parameters
type Numeric type (for example, INTEGER, SHORT REAL). If type
is specified, the numeric function returns a numeric
value of that type. If type is not specified, the
numeric value returned has the default numeric type. A
string function returns a string value.
FNidentifier, Function name. A blank is not allowed between FN and
FNidentifier$ the identifier. For example, if the identifier is Add,
the function name is FNAdd or FNAdd$.
f_param A formal parameter. Formal parameters for multi-line
functions are specified like as they are for
subprograms. The SUBPROGRAM statement explains the
specification.
Example
DEF INTEGER FNAdd (INTEGER A,B(*), REAL C,D(*), E$(*,*,*),F$,G)
DEF FNSearch$(E$(*,*,*),F$, G, #20)
Each of the above statements defines the beginning of a multi-line
function. FNAdd is a numeric (type INTEGER) function, and FNSearch is a
string function.
Each has the following formal parameters:
Parameter Type
A Scalar integer variable
B Integer array variable
C Scalar real variable
D Real array variable
E$ String array variable
F$ Scalar string variable
G Scalar variable with the default numeric type
#20 File designator
If a program has more than one multi-line function with the same name,
the name refers to the first function with that name; that is, the one
that has the lowest-numbered DEF FN statement. The others cannot be
called.
If a program unit has a single-line function with the same name as a
multi-line function, that program unit can only call the single-line
function. Other program units can still call the multi-line function.