Using Subroutines

From Vectorlab

Short introduction to subroutines.

[edit] What is a sub-routine

• Definition on Wikipedia
• Section "User Defined Functions" in the Vectorworks Help > Vectorscript Documentation

TASK

We need to increment a value and at the same time return the value as string. We need to perform this action for 5 times.

There are always more ways to achieve a task. We present here the different subroutines types while achieving the same result.

• Use two subroutines of type "Function"
• Use one subroutine of type "Function" setting a "VAR"

[edit] Use two subroutines of type "Function"

The typical function: it can return only one value.

The routine for incrementing:

• we name the subroutine "IncrementMe"
• we make it a function: it returns an Integer
• we let it have a parameter "int" and a one "howManyMore", both accepting an integer
• add some code to perform the needed actions: increment "int" by howManyMore.
• "IncrementMe" returns the integer passed in the variable incremented by howManyMore.

The routine for converting to string:

• we name the subroutine "MakeMeString"
• we make it a function: it returns a string
• we let it have a parameter "int" which accepts an integer
• add some code to perform the needed actions: convert to string
• "MakeMeString" returns a string from the integer passed in the variable.

PROCEDURE xxxxx;
 
{ variable declaration }
VAR
    myInteger : INTEGER;
 
{ subroutines declaration }
{ returns a value + 1 }
FUNCTION IncrementMe(int, howManyMore: INTEGER): INTEGER;
    BEGIN
        IncrementMe := int + howManyMore;
    END;
    
{ returns the value as string }
FUNCTION MakeMeString(int: INTEGER): STRING;
    BEGIN
        MakeMeString := Concat(int);
    END;
 
{ main block }
BEGIN
    myInteger := 0;
    WHILE myInteger < 5 DO BEGIN
        myInteger := IncrementMe(myInteger, 1); { here the value increments by one }
        AlrtDialog(MakeMeString(myInteger)); { here the value converts to string }
    END;
    
    (* what happens IF you DO this instead?
    WHILE myInteger < 5 DO
        AlrtDialog(MakeMeString(IncrementMe(myInteger, 1))); 
        
        { ENDLESS LOOP! THE VALUE DOESN'T INCREMENT, SO THE WHILE CONDITION NEVER EXITS }
    *)
END;
Run(xxxxx);

[edit] Use one subroutine of type "Function" setting a "VAR"

The advanced function: it can return one value and set any number of Variables (labelled with VAR).

• we name the subroutine "IncrementMe"
• we make it a function: it returns a string
• we let it have a parameter "int" which accepts an integer and a parameter "howManyMore" also integer
• the parameter "int" is declared to be a VAR: any variable employed later while using this routine will be overwritten.
• add some code to perform the needed actions: increment "int" by "howManyMore" and convert to string.
• "IncrementMe" returns a string from the incremented integer passed in the variable.

PROCEDURE xxxxx;
 
{ variable declaration }
VAR
    myInteger : INTEGER;
 
{ subroutines declaration }
{ sets a variable its value + 1 and returns the value as string }
FUNCTION IncrementMe(VAR int: INTEGER; howManyMore: INTEGER): STRING;
    BEGIN
        int := int + howManyMore;
        IncrementMe := Concat(int);
    END;
 
{ main block }
BEGIN
    myInteger := 0;
    WHILE myInteger < 5 DO
        AlrtDialog(IncrementMe(myInteger, 1));
END;
Run(xxxxx);