DYNAMIC-FUNCTION function

Invokes a user-defined function. The AVM evaluates the name of the function (and the procedure handle, if any) at run time.

Syntax 

 

DYNAMIC-FUNCTION ( function-name [ IN proc-handle ] [ , param1 [ , param2 ] ... ] )

function-name

A CHARACTER expression that returns the name of a user-defined function. The AVM evaluates function-name at run time.

IN proc-handle

An expression that returns a handle to the procedure that defines the function. The AVM evaluates proc-handle at run time.

param1, param2, ...

Parameters of the user-defined function. You must supply names of actual data items—actual parameter names—not CHARACTER expressions that return parameter names.

Note:

ABL cannot check the mode and type of the parameters at compile time, since the AVM does not evaluate function-name until run time.

Example 

The following procedure demonstrates the DYNAMIC-FUNCTION function:

 

r-funfun.p 

/* Requires a connection to the Sports2000 database. Define data items */ DEFINE VARIABLE funcs   AS CHARACTER NO-UNDO EXTENT 5   INITIAL ["firstrec","lastrec","nextrec","prevrec","quitting"]. DEFINE VARIABLE action  AS CHARACTER NO-UNDO LABEL "Action" FORMAT "x"   INITIAL "N". DEFINE VARIABLE idx     AS INTEGER   NO-UNDO. DEFINE VARIABLE alldone AS LOGICAL   NO-UNDO.   FORM WITH FRAME x SIDE-LABELS 2 COLUMNS 1 DOWN COLUMN 25.   /* Define user-defined functions */ FUNCTION dispcust RETURNS LOGICAL: DISPLAY Customer EXCEPT Customer.Comments WITH FRAME x. END.   FUNCTION firstrec RETURNS LOGICAL: FIND FIRST Customer. dispcust(). RETURN yes. END.   FUNCTION lastrec RETURNS LOGICAL: FIND LAST Customer. dispcust(). RETURN yes. END.   FUNCTION nextrec RETURNS LOGICAL: FIND NEXT Customer NO-ERROR. IF AVAILABLE Customer THEN dispcust(). RETURN AVAILABLE(Customer). END.   FUNCTION prevrec RETURNS LOGICAL: FIND PREV Customer NO-ERROR. IF AVAILABLE Customer THEN dispcust(). RETURN AVAILABLE(Customer). END.   FUNCTION quitting RETURNS LOGICAL: alldone = yes. RETURN no. END   /* Main routine */ REPEAT WHILE NOT alldone: UPDATE action HELP "Enter F(irst), L(ast), N(ext), P(rior), or Q(uit) to navigate.". idx = LOOKUP(action,"f,l,n,p,q"). IF idx EQ 0 THEN DO: MESSAGE "Enter F(irst), L(ast), N(ext), P(rior), or Q(uit)"       VIEW-AS ALERT-BOX. NEXT. END. DISPLAY DYNAMIC-FUNCTION(funcs[idx]) LABEL "Record Found?". END.

See also 

FUNCTION statement