Unchangeable GLOBALS

[jcfuller]

Here is a little snippit where you can define GLOBAL variables which cannot be change.
Can be used in place of BYCOPY or as a substitute for EQUATES.

James

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'SED_PBCC
' An example of using a class to create GLOBAL variables that can be passed BYREF
' where the original cannot be changed outside the procedure.
'=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*
#IF NOT %DEF(%Prop_MACROS)
    %Prop_MACROS = 1
    MACRO PropGet(PropName,PropType)=PROPERTY GET PropName() AS PropType:PROPERTY=PropName:END PROPERTY
    MACRO PropSet(PropName,PropType)=PROPERTY SET PropName(BYVAL param AS PropType):PropName=param:END PROPERTY
#ENDIF
'Return Nacros
#IF NOT %DEF(%RET_M_MACRO)
    %RET_M_MACRO = 1
    MACRO Ret_M(RetVal) = METHOD=RetVal:EXIT METHOD
#ENDIF
#IF NOT %DEF(%RET_F_MACRO)
    MACRO Ret_F(RetVal) = FUNCTION=RetVal:EXIT FUNCTION
    %RET_F_MACRO = 1
#ENDIF
'******************************************************************************
CLASS cConst
    INSTANCE Id1,Id2,Id3 AS LONG
    CLASS METHOD CREATE
        Id1 = 1
        Id2 = 2
        Id3 = 3
    END METHOD
    INTERFACE iConst : INHERIT IUNKNOWN
        PropGet(Id1,LONG)
        PropGet(Id2,LONG)
        PropGet(Id3,LONG)
    END INTERFACE

END CLASS

GLOBAL Const AS iConst


FUNCTION PBMAIN() AS LONG
        Const = CLASS "cConst"
'Now Const is available throughout your program
        PRINT "In PbMain Before TestIt Call";Const.Id1
        TestIt Const.Id1
        PRINT "In PbMain After TestIt Call ";Const.Id1        
        TestIt02
        TestIt
        WAITKEY$
END FUNCTION


FUNCTION TestIt(OPT L1 AS LONG) AS LONG
    IF ISMISSING(L1) THEN
        ? "L1 is missing"
        RET_F(0)
    END IF    
    ? "L1 = ";L1
    INCR L1
    ?"L1 = ";L1
END FUNCTION

SUB TestIt02()
  TestIt Const.id3

END SUB

[Michael Mattias]

Isn't this kind of the long way to "paying attention whilst programming?"

Then again, using this techinique you could be producing typical Microsoft Visual Anything-quality applications in no time.