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Templates: Checking if template instance exists
1998-09-08 -- Brian Staff
 
Newsgroups: topspeed.products.c4

> I am writing a Procedure Estension template.  This template call a
> function at %ProgramSetup.  However, when I include this template in
> more than one procedure, it generates that function call for each
> procedure it is included in.  I only need the function called once
> regardless of the number of procedures that include this extension
> template.
>
> How can the above be done?

 #DECLARE(%FirstInstance)
 #DECLARE(%LastInstance)
 #DECLARE(%ThisTemplate)
 #SET(%ThisTemplate,%ActiveTemplate)
 #!do NOT put the UNIQUE attribute on the following DECLARE - it will cause
 the ADD to sort
 #DECLARE(%AllInstances),MULTI
 #FOR(%ActiveTemplate),WHERE(%ActiveTemplate=%ThisTemplate)
   #FOR(%ActiveTemplateInstance)
     #ADD(%AllInstances,%ActiveTemplateInstance)
   #ENDFOR
 #ENDFOR
 #SELECT(%AllInstances,1)
 #IF(%AllInstances=%ActiveTemplateInstance)
   #SET(%FirstInstance,1)
 #ELSE
   #SET(%FirstInstance,0)
 #ENDIF
 #SELECT(%AllInstances,ITEMS(%AllInstances))
 #IF(%AllInstances=%ActiveTemplateInstance)
   #SET(%LastInstance,1)
 #ELSE
   #SET(%LastInstance,0)
 #ENDIF

 #AT(%GlobalData)
 #IF(%FirstInstance)
 Myvariable LONG
 #ENDIF
 #ENDAT

This technique also allows you to build complex structures like:
 #IF(%FirstInstance)
 CASE MyVariable
 #ENDIF
 OF Whatever !one for every instance
    DO Something
 #IF(%LastInstance)
 END
 #ENDIF

HTH

Brian Staff (Phoenix) - Team TopSpeed [CW]
http://ourworld.compuserve.com/homepages/BrianStaff/



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